: Lets see going by the scientific reasoning that sex is for reproduction and made so pleasurable as to encourage the species to reproduce I'd say that heterosexuality is the most natural sexuality.This is not the case. Sex has multiple functions in primate society. This can be demonstrated by a) the fact that women are fertile all year round and b) by the female orgasm.
a) first. Menstruation takes energy; it also renders women less efficient at certain times of the month (as anyone who has ever had to provide hot water bottles for a girlfriend with serious cramps will know!).
If sex were purely for reproduction, then it would be much more sensible in biological terms if primates worked the same way as other large animals; to have a period in oestrus ("on heat"), either once or twice a year; especially given that the human gestation period is nine months - it is pretty unlikely that fertility would be required or useful more than once a year. It is not. Thus, reproduction is not the only motivator in sex. In fact, as has been demonstrated repeatedly, sex in primate societies takes a triple role; firstly, the reproduction of the species; secondly, recreation; and thirdly, social bonding.
Only the first of these is exclusively heterosexual. The other two functions are non gender-specific; this may seem like a triviality, but most primates are observed to exhibit bisexual behaviour, as Nikhil remarked.
Secondly, the female orgasm; it's function is *not* to encourage women to reproduce; rather its function is to encourage pair-bonding between couples; as such, pair bonding between same-sex couples is as valid as a bonding between straight couples.
The scientific evidence puts us fairly firmly in the primate family, which exhibits bisexuality. So much for it being unnnatural.
: Because of the pain involved in unintended penetration, speaking of male homosexuality here, I think it's also safe to say it could be associated with sadistic and cruel motives, also right wing beliefs.
It's not something I've ever done or intend to do, but I am reliably informed that it's no more painful the heterosexual penetration. Does heterosexual penetration ever hurt women? Does that make straight sex a fascist act?
As for the "sadistic and cruel motives"; there were people who said that about straight sex in Victorian England; the female superior position has been held to be degrading to men; in what way is your statement any more qualified than those? As I've said, it doesn't hurt (apparently).
: I'd also like to say that whether or not we once where chimps or not I'd like to think that we have evolved beyond their norms of behaviour.
Why? In what way are we "superior" to chimps? We are primates; we may have evolved into suit-wearing primates, but we have no reason for assuming our superiority over the rest of the world other than religious beliefs.
(And hey, gorillas don't go around killing each other for being the wrong colour, or stockpile what they can't ever use and restrict others from using it...)
Farinata.
None.
