Lastly, your brother and sister are not you and I can't even find the words to show the absurdity that somehow nature 'knows' how to give your bro and sis a leg up for you.
I can find the words for this absurdity: "creationist strawman". Nature
knows nothing. However, natural selection favors genes which promote the spread of those genes through the gene pool, which is obviously achieved by any gene which promotes the well-being of one's siblings' children. (See also: ants, bees, naked mole rats.)
And to further elucidate the point, it still does nothing to explain why they have sexual urges, if most evolutionists claim that the sole reason for sex is to proliferate.
'Cos gay people have the same nerve endings as everyone else.
You are confusing two issues: the reason why sex exists, and the reason why people have sex. Sex exists 'cos it spreads your genes; the reason people have sex is 'cos it's fun. (See also: masturbation, fellatio, anal sex between heterosexual couples,
et cetera.)
Edited by Dr Adequate, : No reason given.
Edited by Dr Adequate, : No reason given.