re: #781 Irenike

But every organism, if the population is big enough, has brothers and sisters who will bear successful offspring. That does not mean that unsuccessful “aunts” and “uncles” will still see their traits passed down to subsequent generations for very long. If that were the case, then certain traits would never die out, and hence there would be no evolutionary progress.

How is my line of inquiry flawed?

Sociobiology argument:

1) gay aunts and uncles may contribute to the successful upbringing of their nieces and nephews.
2) those nieces and nephews are likely to carry some of the genes that predispose to homosexuality, even if those genes are not expressed.
3) those genes are then passed to the next generation.

Heterozygote advantage argument:

Take sickle cell disease. This is a nasty inherited disease in Africa. Get a sickle cell gene from each parent, you will likely die before reaching reproductive age. Yet, inherit one gene (sickle cell trait), and you are relatively resistant to malaria, and therefore have a survival advantage over someone with normal hemoglobin genes. There are many, many such examples.

It could well be the case that inheriting some but not all of the “gay” genes (it is likely that there are more than one so that the inheritance is more complex than for sickle cell) confers a survival advantage.