I don't have flawed logic. Speaking strictly from an evolutionary point of view homosexuality is something that would die out.
Strictly analitically speaking, why would evolution create homosexuality, yet the body remains the same to reject it, and the sexual result ends in the dying of that species.
You keep assuming there are heterosexuals to continue the race. If homosexuality were an evolutionary change then you can not expect that. If evolution brought around this change it would also bring about a way to procreate. If you are telling me that a homosexual man can be sexual attracted to a heterosexual woman to be able to procreate I think you are opening up a can of worms, and ultimately bring the whole theory into contradiction of itself.
If homosexuality is part of evolution then it would have to have a predominantly genetic basis.
This is not, as far as I'm aware, a given- but let's assume it is for the moment.
Not every genetic trait manifests in each carrier. Some genes are regressive- for example hair colour.
I have blonde hair, but neither of my parents do. However, both carried the blonde hair gene which was passed to me from both sides. If only one had passed on a dark hair gene then I would have dark hair but I could still pass on the blonde hair gene to any children of mine.
Or to look at a less benign condition- sickle cell anaemia. Carrying the genes for it without having the full condition gives a high resistance to malaria, so there was a benefit to having this. However, when the genes are reinforced the resultant condition could and did cause high infant mortality before the condition was properly studied, analysed and treated. Evolutionarity speaking, it was 'better' to loose a number of children when they were young than to loose a larger number of adults to malaria.
http://en.wikipedia.org/wiki/Sickle_cell_anaemia
A wide varistion in genetic makeup is a survival trait. If all people were essentially the same in terms of genetic traits such as immunity then one illness could wipe out the entire population. The Black Death, for example, infected killed large amounts of varous populations, but some people were immune or had an immune system that could fight it off and they were the ones who could pass on this trait to their children.
Basically, evolution can produce traits that, if common to all people, would indeed signal the end of the species; sickle cell anaemia, a particular immune system. But in the same way, evolution means that not everyone will have the same trait.
Diversity equals survival.
To apply this to homosexuality- there is a tentative hypothesis that the development of homosexuality was in some way a response to over-population pressures. It promotes pair-bonding, which is beneficial to society, and increases the number of adults available to increase resources without also creating drains on these resources, as in early societies the high infant and child mortality rates would mean that resources would be used up without the expected repayment from the child when they grew up. But this is still in the hypothesis stage as there is an incomplete understanding of the mechanics a)behind why some people are homosexual and b)how this pressure would trigger homosexuality in the first place.
Still, it's an interesting thought, which would mean that homosexuality
is evolutionarily beneficial.
The problem with arguments from biology, though, is that it suggests that things such as love and attraction are purely chemical responses- this does not appear to be the case. There appears to be a strong mental componant as well, relating to the mind and consciousness as opposed to the brain and body.
It really is a fascinating field of study which may never be fully explored and answered, but there are no indications of non-societal reasons (i.e. reasons that don't boil down to 'My God says it's wrong' or a personal 'ick' factor) why there should be a problem with homosexuality.
BTW, a 'homosexual' man who is capable of being sexually attracted to women is a bisexual man. If he had to close his eyes and think of Brad Pitt, then he really is fully homosexual.
