The Consanguinamory Reproduction Study… The results are in!

Okay folks, as some of you likely remember I was running a study on consang reproduction, to determine the risks.

There were 133 respondents, 18 of which had to be eliminated from the study either because they had no children, or gave logically impossible answers. This leaves us with a sample size of 115 couples who between them had 226 children (136 Girls, 88 Boys, 1 Intersex and 1 Gender Undisclosed)

Sixteen of the couples who responded were themselves the result of a pregnancy between first degree relatives, and three were the result of cousin pregnancies.

22 Children were born prematurely, 18 were overdue, two pregnancies were aborted, and the remaining 184 were born ontime.

21 of the children suffered from an illness, 14 of which the participant specified as a ‘common illness’ These included allergies, asthma, autism. Four of the children suffered from illness or disability which the participant is certain is down to inbreeding, and five are unsure what caused the illness as it is uncommon.

16 children had learning disabilities (16/226 x100 = 7.1%), 9 of which were also specified as children suffering from an illness.

The total number of children with ANY problem at all is 21 + (16-9) = 28

This gives brings us to the overall illness and disability rate of : 28/226 x 100 = 12.4%

However, if we were to exclude children suffering from common illnesses (eg. asthma) and learning disabilities (eg. ADHD) which occur frequently in the children of regular couples, we get (28-14)/226 x 100 = 6.2%

If we include only the four children who we are absolutely certain suffered illness as a direct result of their parentage, we get 4/226 x 100 = 1.8%

Confounding factors:

1. Is my sample size too small to take a true reading? It could be possible, 115 couples is not a very large sample, however, I believe it is sufficient to take a snapshot.

2. It is possible that parents of children who are disabled due to inbreeding have not found their way to the community, and therefore my study? If so, this could be a biased sample.

3. Is it possible that some mothers felt uncomfortable seeking adequate medical care during their pregnancy in case the parentage of the unborn child was discovered? This could have lead to more health problems for the mothers and children in question.

4. Is it possible that mothers who are pregnant via consanguinamory take better care of themselves throughout their pregnancy to try to mitigate the believed extra risk associated? In my study: a. Only 16 (7.1%) did not eat a balanced and varied diet, b. 13 were exposed to a toxin of some kind during pregnancy (only 8 (8/226 x 100 = 3.5%) of which were tobacco, alcohol or recreational drugs, the remainder were environmental toxins and medications). This would indicate an overall careful attitude during the pregnancies.

2^nd Generation inbreeding calculations

42 children were born from parents who were themselves conceived by related parents.

Of these children:

8 had a common illness

4 had learning disabilities, bringing the total to 12.

12/42 x 100 = 28.6%

The risk more than doubles for the second generation. This proves the theory correct that the risk increases with each subsequent generation of inbreeding. While nature allows for consang relationships and children to be born from them, it does not allow for many subsequent generations to practice inbreeding. It goes a way towards explaining the gene pool of Ancient Egypt, where up to one in 5 pregnancies was conceived via consanguinamory, and yet there was no mass disability… there was enough outbreeding to balance that and thus maintain the health of the gene pool. However the royal dynasties of that empire had to marry within the family for religious and political reasons, leading to inbreeding depression, disability and eventual sterility in the offspring.

Bottom line

The overall risk of a child being unhealthy in the first generation is 12.4%, in real terms a one in 8 chance. This may sound like terrible odds, but when you consider that this figure includes common chronic conditions which are also becoming increasingly prevant in the regular population also, and that when these conditions are excluded, and we include only uncommon problems (which are more likely to be expressed with two copies of the same defective gene), and problems we know for sure are a direct result of consang reproduction (only 1.8%), the ADDED risk is a mere 6.2%. Odds are strongly in your favour that nothing is going to go wrong as a direct result of consanguinamory, providing that your parents are not related.

The news is however not so great for those who are involved and wish to have a family whose parents were also close relatives. The risk is more than double for your prospective children than it was for you as generation one. Based on this I would advise against second generation inbreeding. That said, you can still have children, just not in the way you may have imagined. You have options such as using a sperm bank or surrogate. This way you get the best of both worlds, a safer way to have children.

I can’t tell anyone what to do, but what I can do is bring you the facts and trust that you now have the knowledge to do what is right for your circumstances. There has been very little research into the field of consang reproduction, professionals won’t touch the subject with a bargepole, and considering the illegality of incest in many places and the sensitivity of the subject, people will only come forward anonymously. What I have provided here is not absolute nor irrefutable,  it is simply one body of evidence which needs to be joined with several more bodies of evidence in the future. The figures I calculated may be approximate only due to the relatively small sample size, but they do give us the general idea.

As a final note, I would like to thank the couples who took part in the survey, you’ve done a great service to other consangs who are sitting there debating whether or not to have a child. The information you provided could help those couples to make the right choice for them.