Quote:
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Originally Posted by Mantus
- Incest has the problem of causing genetic disorders in offspring and thus future generation’s health.
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As I mentioned in a previous post, this is clearly not a valid argument.
Incest does not
cause genetic disorders. Members of the same family are likely to share the same predisposition to particular medical conditions.
So for example, Alice and Bob are siblings and both carriers of cystic fibrosis (CF), passed on from a parent. There is a 25% chance of any offspring of this union developing CF and a 50% chance that it would carry the gene but show no symptoms, like Alice and Bob.
If Alice had instead decided that incest was not her thing, and met Chris who is not a CF carrier, their children would have a 0% chance of developing CF and a 50% chance of being a carrier.
It would appear that incest is more likely to result in offspring with genetic disorders. However, if Alice meets Dave who is another CF carrier, the chances are exactly the same as with her brother.
Does that mean that it should be illegal for Alice to have relations with anyone who tests positive for the CF gene?
There is also the issue of contraception, which seems to make this argument against incest a little pointless.