This site is about Buddho-Darwinism so where does that leave sexuality.
Clearly in Darwinist terms sexuality is about reproduction.
In Buddhist terms it is said Buddha left his wife and son to seek enlightenment, troubled by al the suffering in the world. This leaves the wife with little sexual options but to take a lover or continue in the way a war widow might do, stoically supporting the child but reflecting on lost love. Since the times of Buddha though, in some traditions, the practice of Tantric sex has developed. In this the representations of woman are that the female has wisdom where the man has compassion.
Without emissions of semen there would be no reproduction so clearly if the most compassionate men, which I will say would be the best for the world as fathers, for the sake of this argument, did not engage in ordinary sex from time to time, with females not using contraception, then the only those with the least genetic propensity for compassion might reproduce.
This is actually more of a problem than might be realised. If only domineering alpha males reproduce will there ever be peace on the planet or will the human race tear itself apart in a war for the diminishing resources, per person, of the world, as the population increases?
Returning to Tantric sex, I am amazed by how much in non-Buddhist cultures this same balance of female wisdom and male compassion is shown. The Bangladeshi women, in Monica Ali’s book “Brick Lane”, have wisdom, understanding their men folk, while the best men have compassion in various degrees where the women accept that it is good to have a man who does not beat them, (some men in that culture obviously do that).
I can only recommend studying writings on Tantra to understand Buddhism and sexuality further.
One Buddhist text I read talked of sex sapping the intellect whereas a scientific paper stated it stimulated the intellect. My own conclusion is that what might be seen as intellect in Buddhism, namely the ability of the mind to connect to the other realms of spirit and life outside normal parameters of reality is what is being referred to by that term when used in a Buddhist context and not IQ. IQ may well be stimulated by orgasms but I would wait for scientific research to confirm that.
Fundamentally then, Tantric sex may be a way of preserving the intellectual connections with the infinite, with compassion and with love, without abandoning relationships for the life of an ascetic monk or nun.