25th Jan 2015

A Treasured Love Denied Marriage

From Full Marriage Equality:

I have one sibling and that’s my half-sister who I’m in a relationship with. I have a son from a previous relationship; let’s call him Billy Jr. Currently I live in the UK. It’s illegal here to marry or be with any family member including family members who are married into the family such as step-fathers, step-mothers, step-sisters, step-brothers.

[…] Growing up, we never met; not once. I had heard about her from time to time over the years but never thought anything of it. I never really saw my dad a lot. Couldn’t say I wanted to. […] He mentioned her a few times but told me because he’d never been in her life, she never met him once, and that I couldn’t get in contact with her and that was the end of it. He passed away and somebody told her about it a year on. She looked him up and found out about me. She contacted me and it went from there. […] Growing up, I always wanted a sister and she always wanted an older brother so we were overjoyed to have found each other.

[…] I noticed straight away, when she added me on Facebook. The first thing I thought was “pwoarrrr she’s gorgeous” when I looked through her pictures. At first I thought nothing of it because some brothers have no problem thinking their sisters are beautiful. It wasn’t until I met her for the first time that I noticed the attraction was more than any brother should have for his sister. I felt a spark from the moment I laid my eyes on hers.

When she gave me a long, emotional hug, nothing ever felt as right as it did in that moment. I felt safe, protected, loved, every positive feeling possible in one hug. It’s like nothing I ever felt before. The whole time of being around her, I smiled, my eyes kept catching hers, her eyes kept catching mine, we had the most sincere unforced smiles on our faces, it was the first time I ever seen anybody’s eyes twinkle for me.

[…] I kind of noticed it way before we ever did anything, way before we even kissed.  We would cuddle constantly. We thought it was just because we were close. Well I say that, but I think that was something we said to mask our deeper feelings for one another.

[…] Our first kiss was when we were watching a movie and I told her she was beautiful. I was stroking her hair with her head on my chest. She looked up at me and I thought “okay here comes twenty [pecking kisses] in a row.” By the time we made it to the tenth peck kiss I noticed her mouth opened a little and her tongue gradually met mine. From there it spiraled into pure passion. We stopped to look at each other and say “this is crazy,” “did that just happen?” Neither of us cared either way.

[…] Quite a few people know about us. They had to know, because we told people beforehand that we were half-brother and half-sister. Our grandad on our dad’s side was the first person to encourage me by saying “I can tell you have a thing for each other, it’s obvious. If you ever find out she feels the same one day, don’t be shy and don’t let nobody tell you it’s wrong. If they got a problem, buggar ‘em.”

I told my family and they just accepted it. I told three of my closest friends. A joke here and there, but they didn’t care. One didn’t agree with it from his own beliefs but said so long as I was happy, he’d support me on it.

Her mother didn’t agree with it and is dead set against it even. She wouldn’t even discuss it or hear out an opinion that wasn’t hers; just gave us reasons to feel ashamed.

We don’t really act like a couple unless we are behind closed doors. If we’re in a place where nobody knows us, it’s great. Nobody realizes a thing and we can act like a couple. Other than that, we had to delete our Facebook accounts as people were getting suspicious and I just really didn’t like the idea of being on there as brother and sister only. It felt really heartbreaking knowing we couldn’t say we were more, so we prefer to live our lives in private away from that sort of stuff.

[…] Having to hide away has just been very exhausting and anxiety producing. We know we haven’t done anything wrong to anybody; we haven’t harmed anybody either, yet we feel like were criminals on the run just waiting to be caught.  Personally, I couldn’t care less what people think about our relationship. If the law didn’t have a say in the UK, I would happily walk around with my head held high. At times there’s been a lot of heartache and tears, mostly because we realize we hit the ceiling quite a lot with the limits we have. We both have circumstances that prevent us from living together and living each day as a happy couple together, mostly due to peoples’ opinions on our relationship, yet even with all that in mind, it’s not something I’d trade for anything in the world and I’ll happily fight whatever comes our way, even a jail sentence if I have to, just to be with her, because I couldn’t ever be happy being without her.

[…] I had a friend I went to school with. He was in a long-term relationship. I was friends with him all the way through college. He found out his girlfriend of eight years was actually his full-blood sister. She was a year younger than him and at the time his parents gave her up through being too young to have two children. She was adopted and knew nothing about her birth parents or him. When she looked into it, that’s what they found out. Everyone on both sides was against it, wouldn’t hear a thing about it. To please people they broke up but lived a good few months in nothing but the worst possible agony I could imagine. It really made me realize why they were so close, even without ever knowing of their connection to each other. He used to tell me it felt like an invisible rope pulling him towards her. Eventually they both caved in and couldn’t bear to be without each other ever again. For most it was weird. For me, it was the sweetest thing I’d ever seen. It actually made me tear up. They live abroad now and because they have different last names, they managed to get married; credit to them.

[…] One day I hope to marry my half-sister, or at the very least, live with her and live a happy care free life where it isn’t illegal to love and be with each other. I feel torn in half when she isn’t in my arms. It’s a dream at this point in time but hopefully one day it’ll be a reality.



A Treasured Love From Her Perspective

The other half of a beautiful relationship, from Full Marriage Equality:

[I and my half-brother] didn’t know each other growing up. I always lived with my mum and other siblings; none of them knew of my dads side of the family. My half-brother was told he couldn’t contact me and I only knew of him when someone on Facebook told me our dad, who I never knew, passed away. […] I contacted my brother and we hit it off straight away, talking for hours online, by texts, and by phone calls. I knew there was a strong bond from the start. I always wanted a big brother and he always wanted a sister; that in itself made it even more special to us. We were over the moon to be able to talk and finally meet each other. 

[…] The first time I [saw] his photo, I thought he was very attractive and looked like a lovely, sweet, kind person. I couldn’t wait for us to talk and hopefully meet up. Just looking at his profile made me so proud to have him as a big brother. I had the feeling we would be close from the start.

We were so happy to finally talk and when we met in person, the second we looked at each other it was very emotional and overwhelming. We hugged for what seemed ages, like we never wanted to let go. There was an instant connection. I felt closer to him than I’d ever been with anyone. He held me tightly and I did the same. I’d never felt so loved and cherished up until that moment. We could tell how much we meant to each other. Our eyes lit up, our endless smiles said it all. It was an incredible feeling.

[…] One night we were watching a film on TV and I leaned into him for a cuddle. My head was on his chest, my arms wrapped around him and, he stroked my hair and told me I was beautiful. I looked up at him, we smiled at each other. I kissed him on the lips. We were always gave each other pecks continuously, nothing more up until that moment. We kept kissing and I couldn’t hold back, I didn’t want to hold back, I opened my mouth a little and he did the same. Our tongues met and we had the most passionate, loving kiss imaginable. We looked at each other with a slightly shocked yet relieved look on our faces. Knowing we both felt the same, was the best feeling in the world. I felt complete from that moment.

[…] After that kiss we spent hours cuddling, more kissing, touching, then went up to his bedroom and experienced the most amazing, breathtaking, passionate love making imaginable. We connected in every single way; it felt like we were one. I had never thought I would ever experience anything like it. It was magical, every precious second, like heaven to me. 

[…] Making love with him is the most amazing feeling in the world, physically, emotionally and spiritually. There’s so much love and passion between us. It’s an intense feeling. I think there will always be that “kinky” side to it, as we see each other as both sister/brother and girlfriend/boyfriend. Like he also says, it is like neither I nor him had ever made love before. It’s like our hearts could touch. We’re that close and inseparable.

[…] We see each other as siblings, soul mates, and partners. We are fully committed to each other. I couldn’t see myself with anyone else and he says the same too. We want and plan to live together soon, and hopefully, one day, get married. He makes me feel amazing in so many ways. I couldn’t have wished for a better person to have this unique relationship with. Our love really is, as he says too, the treasure that cannot be stolen.

[…] A few people know about us; only close family and friends. We told them. Most weren’t phased by our relationship, mainly on his side of the family. Some were and are against us being together, which unfortunately are family members on my side. Our Granddad, our dad’s dad, encouraged us to be together as he could see there was something between us. He is happy for us too. We really only act like a couple behind closed doors. We would love to be able to be this way in public. We deactivated our Facebook accounts due to people not minding their own business and spouting their unwanted opinions about our photos together. We could never tell everyone the truth about us. It’s a shame that society and the law are this way. We’re proud of the relationship we have and given the chance would tell the world if we could.

[…] Everyone has the right to be with and marry who they want to, as long as both are of age and consent. My half-brother and I are two people who adore each other in every way possible and want to live a normal, happy life like every other couple out there. We aren’t hurting anyone. We shouldn’t have to hide or be looked down upon for being in love.

[…] I do not know anyone else in-person who has a similar experience, but I have spoke online and read forums about people in our situation. Some stuck together no matter what, through whatever it took, they went through everything together and came through happy in the end, some went on to get married and have a child or children, some thought it was wrong to feel that way because of law and society, some lived their love lives in private.Everyone’s story is different, especially in consanguineous relationships.

[…] We intend to stay together no matter what. We are in love and our bond is unbreakable. It might not always be easy and we can’t predict what will happen in the future, but together we are strong. We will fight for our right to live as we should be entitled to, as any other happy couple, no matter what it takes.


“Sex and the Siberian Neanderthal: Incest and Interspecies Action”

New research is shedding light on the mating habits of our sometime closest relatives.
Researchers extracted DNA from this toe bone of a Siberian Neanderthal female who lived about 50,000 years ago.

The first high-quality genome sequence of a Siberian Neanderthal female is throwing up racy details about our ancient relatives’ sex lives: Siberian Neanderthals mated within their families, the new research shows, while another group, the Denisovans, interbred with Neanderthals, humans and a third, as yet undiscovered mystery hominin living in Asia.

The first anthropologists relied on skull shapes and bone lengths of fossils to identify ancestors in the hominin family tree. Recently though, geneticists have bulked up their toolset, and have identified new species from material taken from mere milligrams of bone. This time, they didn’t even need that. “There is not even a bone splinter here,” Svante Pääbo, a geneticist at the Max Planck Institute for Evolutionary Anthropology, said of the unknown species. “It’s an inference from those other genomes.”

By comparing genetic evidence of the Neanderthal female who lived some 50,000 years ago, with the sequence of a Denisovan girl published in August last year, Pääbo and team discovered a small but discrete signature of a much older species, which the paleoanthropologists suspect might be Homo erectus. The full analysis of the Siberian Neanderthal genome is published in the Thursday issue of Nature.

The entrance to the Denisova cave where researchers came across a fragment of bone from a Denisovan girl’s pinkie finger in 2008, and uncovered the Neanderthal toe bone in 2010.


Inbred bunch

New insights into the Neanderthal genome comes from genetic material extracted from the toe bone of a female found in the Denisova cave in the Altai mountains of Siberia. Using techniques refined in the last few years, researchers extracted enough detail to create a genetic picture of the individual’s parents.

“We can see that the mama and papa of the individuals were very closely related — half siblings or so,” Pääbo said.

There was also a lack of diversity in the genetic material which indicated that sex between closely related individuals within the Siberia Neanderthal community was a regular affair for generations before the girl’s time.

A close read of Neanderthal groups that lived in other parts of Europe would indicate if the practice of inbreeding was common across the species. It is possible, Pääbo said, that the Altai Neanderthals were “such a small population that you’ve hardly any other choice.”

“Identifying inbreeding down to the level of what degree of relation was mating with who is huge!” Ross Barnett, a post-doctoral researcher at the University of Copenhagen who was not involved with the study, wrote to NBC News. “For the first time we are seeing the home life of our extinct relatives.”

I’d be really interested in finding that out myself. Was it merely adaptive behavior, because of their small population in the north, or was it a species-wide breeding strategy? Neanderthal social groups were much smaller than modern human groups.



“Why Marrying Your Cousin May Pay Off”

Oh my god. This is the strongest academic evidence I’ve seen to date. This is the kind of research I’ve only dreamed about. My jaw is on the floor.

In traditional residential societies, couples who were more closely related to each other had more children. By contrast, in migrant societies, related spouses had fewer direct descendants, the research revealed.

[…] “There’s this counterintuitive finding that higher spousal relatedness is related to higher reproductive success in several humans societies,” said Drew Bailey, a psychologist at Carnegie Mellon University in Pittsburgh, and co-author of the study detailed May 21 in the journal Biology Letters.Even in modern, industrialized society, research suggests that people tend to marry others with similar DNA.

[…] In the new study, Bailey and his colleagues examined 46 small-scale societies to compare the effect of inbreeding on the fitness of foragers and non-foragers. The non-foraging societies included horticulturalists, agriculturalists and herding populations, whereas foraging societies were primarily hunter-gatherers. The researchers defined fitness as the number of surviving children in the family tree.

In line with previous findings, the researchers found that among non-foraging societies, a couple’s relatedness was linked with having more surviving children. But among foraging societies, the opposite was true: More-closely related spouses had fewer surviving children. Furthermore, the more family intermarriage in a society, the greater the benefit of intermarrying on the number of children couples had. In other words, in societies in which people frequently married their relatives, intermarrying showed a stronger link to having more children.

[…] There could be many explanations for the different effects of inbreedingshown in the two kinds of societies. Perhaps the best explanation, Bailey said, may be that non-foraging societies are more likely to have heritable resources, such as wealth or livestock, so a tight-knit family group might be more likely to defend each other and their shared resources. By contrast, in a foraging society, it might make more sense to be part of a much larger, interconnected group, since there are few or no resources to be inherited.

It’s tempting to think that people in agricultural societies might intermarry purely out of convenience, since they’re less likely to encounter new people as often as hunter-gatherers might. But that’s not the case, Bailey said. Agricultural societies tend to be much larger than hunter-gatherer ones, so if anything, the reverse might be expected.

[…] Still, it’s hard to untangle whether there’s a causal link between inbreeding and producing more children, Bailey said. Also, because marriages between two closely related individuals are rare in hunter-gatherer societies, the study was based on a small sample, which could have skewed the results.

Clearly, there needs to be more research. There are several things they’re not considering.

For one, notice how in societies that regularly practice consanguineous marriage, such marriages are actually more reproductively successful. They didn’t study disease rates, but rates for cousins usually aren’t high. However, in societies where cousins frequently marry, they’d share a higher percentage of genes than otherwise. This study shows that we actually see an improvement in the number of surviving children.

One very significant possibility is that, as a result of their marriage practices, these societies have re-engineered their genes, and over time eliminated some of their damaging genes by exposing them through endogamy. The larger a population is, the less dangerous “inbreeding” is in the long run for the whole population. Some pockets have good genes while others have bad, and the higher rate of endogamy gives a selective advantage to those families with few harmful recessive genes. Is this actually the case, that, on average, ethnicities with a long history of consanguineous marriage have fewer harmful genes? Is “inbreeding” less dangerous in the long run for settled societies because they have larger populations?

There’s another thing that doesn’t get considered by academics: if, for whatever reason, there’s a reproductive advantage to endogamy, then those who willingly engage in endogamy, and are more willing to have sex with their spouse, would be favored by natural selection. That means that, in settled societies, we should expect to see a higher percentage of people who feel sexual attraction for family. No-one knows what genes are responsible for the Westermarck Effect, so no-one can do any studies on population genetics to see which mutations are prevalent in which regions. The stereotype is that there’s something “incestuous” about Europeans. Is it even true?

And after all, even among wild animals, it’s been observed that rates of fertilization are higher when mates are closely related, because of the higher genetic compatibility between the mother and her zygote/fetus. Is this contributing to the findings?

If their hypothesis is true, then the primary difference in selective success for consanguineous couples is determined by social and economic forces. Exogamy is more socially and economically advantageous in small-scale, hunter-gatherer societies, while endogamy is more advantageous in large-scale, agrarian societies. Is this evidence for the mostly abandoned view, that socioeconomic forces are a prime driver for the development of “incest” taboos?

No-one knows.



Alan Bittles on his own meta-study

[…][If] the data [from my meta-study] are censored to exclude physical and mental abnormalities among the male and female parents, and major disparities with respect to young and advanced maternal age, few differences remain in the overall health outcomes recorded for [the children of the consanguineous group and the children of the control group].

– Alan H. Bittles, Inbreeding, Incest, and the Incest Taboo 

Given the strongly judgmental societal attitudes, direct assessment of the biological outcomes of incest may be subject to significant ascertainment bias, as a rigorous examination, including determination of paternity, may be initiated only if a child shows symptoms of physical or intellectual handicap, or both. The net result is a marked lack of data, which probably does not reflect the actual numbers of incestuous pregnancies that successfully proceed to term. Problems also arise in attempting to control for the potentially adverse effects of nongenetic variables, such as very young or advanced maternal and paternal ages, paternal disease, and unsuccessful attempted interruption of the pregnancy.

– Alan H. Bittles, Inbreeding, Incest, and the Incest Taboo



Danish professor of criminal justice ethics: “Sibling incest should be legal”

A Danish professor responds to the German Advisory Council’s recommendation to decriminalize sibling consanguinamory:



“The supposed depravity of cousin marriage: a moral panic we’d be better off without”

Amen to that. This is so on point:

It amazes me that so few liberal-minded Americans know this, but in fact anxiety over cousin marriage is a peculiarly American thing, the product of the same nineteenth-century anxieties about supposed backwoods degenerates and “corruption of our racial stock” that led to the early-twentieth-century boom in “eugenics.” First-cousin marriage is illegal in thirty states, and an outright criminal offense in five. By contrast, first-cousin marriage is legal in all of Europe save for Romania, Bulgaria, and Croatia, and legal as well in Australia, New Zealand, Japan, Canada, and most of Latin America.

[…] There are genetic risks in first-cousin marriage, but they’re fairly marginal, and can mostly be addressed by getting genetic counseling before having children. For marriages of second cousins and the like, the risks are nearly imperceptible. In fact, if the consequences of first-cousin marriage were as calamitous as many Americans seem to think, the human race would have died out tens of thousands of years ago. For most of history, most humans have lived in small communities and not traveled very far from home; cousin marriage has been extraordinarily common, and yet has somehow failed to yield a planet full of shambling six-fingered freaks.

The problem with finding it hilarious that some states ban same-sex marriage but allow cousin marriage is that you’re basically trashing those states for having laws which are progressive. And when you slam a state like North Carolina with this stuff, you’re participating in a long American history of using cousin marriage as a way of imputing that poor rural people, particularly poor rural people in Appalachia and the South, are depraved, terrifying, and other. Their physical infirmities aren’t products of poverty, malnutrition, and abuse; they’re because something’s fundamentally wrong with them as organisms. It’s not a rhetorical tradition to be proud of.

The comments are gold:

  • A further irony of the “ha ha North Carolina bans gay marriage but lets cousins marry” wheeze: In fact North Carolina restricts cousin marriage slightly more than, for instance, New York State, where all forms of cousin marriage are completely legal. Indeed, the actual list of states that allow unrestricted cousin marriage includes quite a few other states that are neither Southern nor significantly associated with Appalachia, including California, Colorado, Hawaii, New Jersey, Connecticut, Rhode Island, Massachusetts, and Vermont.

  • It’s perfectly legal and socially acceptable in Britain, though rare other than among recent Asian immigrants […] The idea that it is considered harmful in America would strike most of us as weird. […] On the other hand there has been some xenophobic political grandstanding about it in recent years, particularly in parts of the north of England.

  • I always suspected anti-cousin-marriage rhetoric had all the hallmarks of the eugenics movement. The first time this was really brought home for me was in an online discussion around Harry Potter fanfic, in which some British fans said they were sick of Malfoy incest-fic being justified by “they’re aristos, so they marry their cousins, and it’s only a tiny step from that to sleeping with siblings/parents.” Somebody asked “wait – Americans think cousin marriage is incest?” An American asked – “Wait – non-Americans *don’t*?”

    The really horrifying thing, when I investigated further, were the anecdotes about present-day people who were told by their doctors “Well, you seem to have turned out healthy despite your parents having been cousins, but no doubt *your* children will be freaks even if you marry a non-cousin, so you’d better have yourself sterilized.” [Of course that’s not how it works at all. Regardless of your parents, your own kids will be fine if you don’t reproduce with a close relative. Anybody who claims that they have some problem because their own grandparents were cousins, has no idea what they’re talking about.]

  • In 19th century Britain (and its possessions, and to a lesser extent the US) the hot issue for a while was marriage with a deceased wife’s sister. It was the subject of numerous Parliamentary and internal church debates, as well of popular moral panic in some quarters. And it’s almost completely forgotten now.

  • I believe that was a holdover from medieval Church rules about consanguinity, with the logic that “sister-in-law is sort of equivalent to sister, so no marrying them.” (I think this actually goes back to Leviticus.)

  • What’s on my list of History To Learn is how the Christian West’s extensive taboos against consanguinity in the Middle Ages gave way to preferment of cousin marriage in the Reformation and beyond. In the mid-twelfth century, Eleanor of Aquitaine and Louis VII of France’s marriage was annulled technically because they were “related within the fourth degree.” This wasn’t the real political reason, and Eleanor’s next husband, Henry of Anjou, was a closer relation: but the point is that being fourth cousins once removed was grounds for declaring a marriage illegitimate. Contrast this with Victoria and Albert in the the 19th century, who were first cousins and of a family that had long had a habit of marrying inside the gene pool. What gave?

  • Back in the Hellenistic era, the Ptolemaic dynasty consolidated its hold on Egypt by a number of means. One of the more dramatic ones was the theft of Alexander the Great’s body, but slightly better-known is reintroducing the native Egyptian custom of sibling marriage in the royal family.

    Many Greeks, even those in the royal court, found this somewhere between disgusting and outright barbaric, and I use the word deliberately. They considered it extremely offensive that a Hellen(ist)ic royal family should go native to that degree. The Romans were also pretty squicked by it, possibly picking it up from the Greeks.

  • One of the secrets of Egyptian inheritance was that it was in the female line: the husband of the queen ruled, then the husband of the queen’s first daughter ruled. This goes a long way to explaining why Ramesses II, after his sister-wife’s death, married his daughter, and on her death, married another daughter, and on her death, married a third daughter.

  • Come to think of it rules and laws and taboos only make sense if they ban things that some people do but most people don’t. You don’t need laws against cutting your own feet off or eating your own excrement because so few people want to do it there is no need for them. And there is no point in making a rule against something that nearly everyone does because they will carry on doing it anyway – and probably change the rules. The very existence of incest taboos in effectively all human societies is probably evidence that most people don’t do it but enough people do to worry the rest of us.

  • Famously, Darwin’s family was absolutely full of married first cousins (and Charles Darwin was married to his first cousin), and yet seemed to manage to contribute a thing or two to the world. and live relatively good lives.

    At any rate, there are genetic reasons why some people ought not to have kids, either singly or as couples. Not marrying your near relatives is a heruistic for avoiding some of those problems, but you can probably do rather better with modern technology. I know a lot of Jewish couples get genetic counseling to avoid Tay Sachs and a bunch of other related diseases; I assume over time that will become more and more common. Getting married and having kids is surely worth spending a thousand bucks on some tests and an expert to interpret them to head off potential problems.

  • There was a case in Michigan in the 1970s where a married couple discovered that they were full genetic siblings. They’d been given up for adoption and raised apart and unaware of each other’s existence. They argued unsuccessfully that they had no sense of each other as brother and sister, and no common family history, and should be allowed to remain married.

    The judge in the case invalidated their marriage, and forbade them from living together as a married couple…but since in Michigan blood relatives are permitted to live under the same roof, he could not forbid them from living together as brother and sister. How he intended to enforce that distinction is not clear to me, nor did I ever find out what happened after that.

    With regard to the general topic of incest (and cousin “incest”) I think attitudes in the gay community may actually be instructive, since the genetic risk is nil, and everyone knows it is; nonetheless the incest taboo persists. There are those who argue that sex between (male) cousins is incest, and those who think it’s perfectly OK. In the fiction written about this they’re mostly cousins who haven’t seen each other since they were little, removing the family-by-proximity element.

    This is all muddied by the fact that taboo-breaking is eroticized in the gay community; I suspect this arises from the fact that our basic sex drives were taboo growing up, and other taboos get associated with that experience (different ones for different people, of course).

    The result is peculiar in many cases. There’s a set of porn videos showing two “stepbrothers” that became quite popular (for reasons not at all limited to the taboo-cachet described above); some people claimed they knew the participants were actually biological brothers and denounced the videos on that basis, which makes no sense to me, but I guess it triggered their taboo-sense in a way the stepbrothers didn’t.

    It also seems (from my observation of attitudes among gay men) that the taboo is somewhat lessened if the brothers are identical twins, even though they’d plainly be as close genetically as it’s possible to be. Perhaps this is because singleton-born guys can imagine having sex with their own brothers, and react with revulsion; but when they imagine having a twin, they imagine him being themselves, which seems more like masturbation than sex. I’m extremely dubious that actual twins experience each other that way. [They do not. It’s usually more like inverse “narcissism”: they see their lover in themselves, not the other way around.]


What About Donor-Conceived People Getting Together?

Via Full Marriage Equality:

Q: How worried should I be about inadvertent partnering of two donor conceived half siblings from the same donor?

A: This is an issue of concern for many people considering donor conception (donor sperm, donor egg, or donor embryo). While the fear is understandable, many professionals believe the fear is not well founded. For example, we asked this question to Ole Schou, founder and CEO of Cryos International sperm banks, who has researched and spoke to professional groups on this issues. [Note that he is not a native English speaker.]

“There is no reason to be concerned about accidental incest between donor conceived children/adults. The risk is extremely low. Professionals call the risk consanguinity or inbreeding. It is also described as incest. However, this word is surrounded by many taboos and connected to something morally wrong, and is not the best word to use in this situation. If we look into what it really means, it is only relevant for donors in very rare situations. Consanguinity means that the DNA by the two parents are too closely matched. The concern is for the increase in recessive DNA disorders in children where the parents DNA are too closely matched. Remember that all humans have plenty of these recessive genes (C.J. Bell 2011).

However, the risk may only be increased some few percentage in comparison to normal procreation. So this is not much. It is more a problem if it continues generation after generation. Then everybody will sooner or later be affected. This is seen in for instance very small and isolated communities or in royal families. This is not relevant for donors as it is only a one generation issue. Further, the risk that two half siblings from the same donor meet each other is generally very little if the sperm bank distribute internationally or worldwide. For small sperm banks servicing only a little community there should be limits on the number of children per donor–a maximum of 10 according to the American Society of Reproductive Medicine.

Consanguinity is only a question about distribution. For example, 2 children in a rural district induce a higher risk than 100 children in a big city or 1,000 children in a big country or 100,000 children in the world. Today, most large sperm bank distribute nationally or internationally, and it is seldom that a donor father has more than 25 children. In rare cases, it has been reported that there have been more than 150 children from the same donor, but this is not a problem if the geographical distribution is ensured. Also, note that consanguinity by sperm donors are considered to be much less frequent than the general risk in the community (J.L. Serre, 2013).”



Among Great Tits (a type of bird), mating with a sibling is frequently a risk worth taking

The hatching of eggs is reduced by 7.5% for every 10% increase of [consanguinity]. The effect of inbreeding is smaller at the moment of fledging. The recruitment to the next generation at breeding age is not lower from related pairs than from other pairs with the same clutch size in the same year. There is a separate effect on the hatching rate if the female is inbred. However the recruitment from the clutches where either the male or the female is inbred is twice as high as expected. This can be explained because a few individuals have produced many offspring. The offspring have a high chance of mating with a relative, but the adverse effects of inbreeding are offset by higher recruitment. There is no evidence that inbreeding is avoided. Neither is it clear that inbreeding avoidance would be selectively advantageous.

– A.J. van Noordwijk and W. Scharloo, “Inbreeding in an Island Population of the Great Tit”

Basically, less eggs hatch, but they have more eggs to compensate, and their surviving children are actually significantly more likely to reach adulthood than outbred birds, especially when the parents are cousins. The benefits and costs of inbreeding vs. outbreeding are too complex and dependent on other factors for there to be significant evolutionary pressure against inbreeding in Great Tits.



The evolution of inbreeding avoidance is complicated

[…][A]n attempt to mount a purely eugenic argument would be confused because the maladaptive genes expressed when inbreeding is common are not removed from the population by preventing inbreeding. Indeed, inbreeding is the best way of getting rid of those genes in the long run.

– Patrick Bateson, Inbreeding, Incest, and the Incest Taboo

Inbreeding avoidance evolved in part because it helped individuals and their children and grandchildren, on average, not because it made the population as a whole genetically healthier; the genes for inbreeding avoidance propagated more, on average, over time, than their competitors.  Evolution, like life, is more complicated than our taboos.


The Key to Healthy Children for Incestuous Couples

The traditional argument against close relatives having children (besides “Ew, yuck!”) is that they risk a higher rate of genetic disease. Now, I’m not going to get into the old debate over whether a 2% or 4% or 8% increase in disease warrants such a strong reaction. In fact, I’m writing to challenge a basic assumption by both sides in this argument: that the parents’ genes are even the primary problem here; as well as to show that one day soon, we might be able to eliminate most of these risks.

There’s a term scientists have, a catchall phrase, for all the detrimental effects of close genetic mating on a population: inbreeding depression. (It’s the fitness of the population that’s depressed by generations of interbreeding, hence the name.) Inbreeding depression does not occur in the ways or at the rates scientists would expect, if bad genes were the only real cause. Environment can make the difference between consanguineous mating hurting or helping the population, and some species don’t even seem to be affected by interbreeding. (Skip to 2:44 if the link doesn’t do that for you.)

The fact is, we’re all carrying around junk in our genomes that could cripple us, but it never gets turned on. After all, bacteria are cloning themselves, and they seem to do fine, and yet we mammals have increased problems having children with our twins? Doesn’t that seem odd? Well, it is odd.

Where do the increased problems come from, then? The answer: epigenetics. Recently, scientists have realized that which combinations of genes are turned on when, is just as important as which genes you actually have. They’ve discovered that environmental factors over your lifetime chemically alter your DNA, changing the way it’s expressed. These changes over your lifetime can control your weight, your rate of cancer, and more, and you can even pass these changes on to your children. This allows species to evolve quickly without having to even change their genes.

The most powerful epigenetic process is called DNA methylation. Methyl compounds bind to your DNA, inhibiting certain genes. If you have too little methylation, harmful genes accumulated over the life of our species can get turned on, causing diseases such as cancer. If you have too much methylation, many important genes can fail to turn on, and your cells won’t properly coordinate or function, leading to developmental problems or miscarriage.

But this all comes with some miraculous discoveries! Recently, several research papershave shown that many of the bad side effects of consanguineous mating that we previously thought were caused by bad shared genes (a.k.a. inbreeding depression), aren’t caused by bad genes at all! They’re caused by epigenetics, specifically too much methylation during the embryo’s development.

But this is actually great news, because the epigenome is easier to modify than the genome. There’s something even more amazing that came out of that first paper: the way they tested their methylation hypothesis was by curing their experimental group of inbreeding depression! (The test group members were bred with themselves, which is as close genetically as you can get.) Yes, we might have the technology now to eliminate most of the extra risks consanguinamorous couples face when having children! Unfortunately, the treatment’s not commercially available – epigenetics is too new a field. However, it is something we can look forward to.

Because your epigenome changes over your life, and affects the epigenome of your children, there should be steps you can take now to decrease the likelihood of problems your children would face. (This goes for all couples, not just the consanguinamorous.)Lifestyle choices, like chemical exposure, diet, and exercise affect your epigenome. Unfortunately, there’s not enough research on the epigenetics of consanguineous mating for me to really tell you what you would have to do. If you’re curious, consult a doctor, perhaps they have some more insight than I can give on specific actions you can take.

Edit: Further research provides some practical advice!


More help for ensuring healthy babies for incestuous couples

I’ve written previously about experiments showing that epigenetics are possibly the primary factor in reducing the fitness of offspring to genetically close individuals. (They proved it by curing the inbred plants of their problems with a simple chemical treatment.)

Excessive methylation of the embryo’s genome during development in the womb leads to too many genes being turned off. This over-methylation may be caused by the child receiving identical copies of the same methylation control gene from both parents. When the copies are identical (a.k.a. homozygous), they are expressed too strongly in the embryo. Fortunately (and unfortunately), methylation is affected by the behavior and diet of the parents. This means that if consanguineous parents change their diet, they can improve the health of their future children.

More research has come out about methylation and diet. The study focused on children of impoverished parents, but less methylation is exactly what the children of consanguineous parents need. They found that two compounds – cysteine and homocysteine – were highly correlated with lower levels of methylation in offspring. Homocysteine and it’s precursors are dangerous for personal health in high levels, but cysteine is important in many processes (like reducing heavy metals in your blood).

Cysteine can be found in these foods:

  • pork
  • poultry
  • eggs
  • dairy
  • red peppers
  • garlic
  • onions
  • broccoli
  • brussels sprouts
  • oats
  • wheat germ
  • sprouted lentils

Homocysteine can also be increased on its own, or by increasing methionine, but both are riskier. Talk to a doctor first, if you can find one you trust.


New Drug Helps Huntington’s Disease Afflicted Mice and Their Offspring

An article from Neuroscience News brings attention to great new research:

Famine, drug abuse and even stress can “silence” certain genes, causing health problems in generations to come. Now scientists are wondering–could therapies that change gene expression in parents help their children?

A new study from scientists at The Scripps Research Institute (TSRI) suggests this is possible. The research showed that the offspring of mice treated with a drug also had delayed onset and reduced symptoms of Huntington’s disease, an inherited, degenerative disease that causes a loss of motor skills, cognitive impairment and death. This was the first time scientists have shown that drug compounds that benefit parents can also cause changes in genetic expression that benefit offspring–in this case, improved memory and motor skills.

“One exciting aspect of our study is that the parental drug treatment made the offspring better, not worse, like other compounds known to cause transgenerational effects,” said Elizabeth Thomas, associate professor at TSRI who led the new study. Thomas and her colleagues report their findings online ahead of print in this week’s Early Edition of the journal Proceedings of the National Academy of Sciences.

Compound Shows Potential

The Huntington’s Disease Society of America estimates that more than a quarter of a million Americans have the disease or are at risk of inheriting it from a parent. Thomas began studying Huntington’s disease 15 years ago, when she found out that a close friend’s mother had the disease.

“If your mom or dad carries the mutation, you have a 50-50 chance of inheriting the disease,” said Thomas. Although there is a test to see if a person will develop Huntington’s, Thomas said many people don’t get tested because there are no good treatments to prevent or reduce symptoms.

Thomas and other scientists at TSRI have been testing compounds called histone deacetylase (HDAC) inhibitors to see if they can induce “epigenetic” changes to help lessen the severity of diseases such as Huntington’s. Epigenetics refers to changes in gene expression–triggered by diet or toxins in the environment, for example–that are not caused by changes to the genetic code. While the genetic sequence itself remains unchanged, epigenetic changes can be passed to the next generation and have been linked to conditions such as obesity and autism-related disorders. Epigenetic changes are often caused by DNA methylation, a process where a methyl group is attached to DNA, silencing gene expression.

Looking Ahead

With the new results from mouse models, Thomas is curious whether the effects of HDAC inhibitors could be passed down through the female germline, and whether the beneficial effects could persist in generations of grandchildren or great-grandchildren.

The scientists are also interested in the effects of other types of HDAC inhibitors already approved to treat certain cancers and bipolar disorder. “Many patients with these diseases have kids, so a big question is how these treatments might affect their offspring,” said Thomas.

This is great news for everybody. We may be able to make significant improvements in people’s genetic health, curing many, many diseases, before we even have a handle on genetic engineering. One day, your medication for bipolar, depression, or anxiety might also inoculate your children and grand children.

This is especially important news for consanguinamorous people, though. As I’ve written about before, the consequences of reproducing with a close relative are exacerbated by epigenetic effects. Because epigenetic markers are passed on to your children, adults can affect their children’s health outcomes through lifestyle changes. It’s not a real fix for the problem, though. Drugs like this, and other compounds being used in experiments, have the potential to almost eliminate the health consequences for the children of consanguineous couples.

There will likely be a day in our own lifetimes where the eugenic argument against consanguinamory will be considered ridiculous and medically irrelevant.