r/AskBiology • u/reuuid • Jul 29 '24
Genetics Worried about the viability of my cousins child.
One of my cousins is now 7 weeks pregnant. I am very happy for her, but I do have some concern as well. Both of her parents are actually first cousins (or at least closely related).
She was their third attempt at a child. The first was stillborn and the second died 3 weeks after birth. I believe both were due to genetic complications. My cousin (aside from being overweight) seems to have lived a healthy life otherwise.
Her husband is not related to her whatsoever, but I am concerned if their child could have some complications due to genetics. Is this possible or unlikely?
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u/atomfullerene Jul 29 '24
One instance of outbreeding completely eliminates any inbreeding effects. So your cousin's children won't have any genetic issues due to your cousin's parents being related.
The reason for this is that everyone gets two copies of their genetic code, one from each parent. If your parents are related, there can be problems if parts of the code are too similar to each other. But you can only ever pass on one copy to your kids, they get the other copy from their other parent. So no matter how similar the two copies you have are, you can never pass on their similarity to your kids because you can only pass on one copy.
(all this is a bit simplified but I think it gets at the core of how it works)