I saw "Kinsey" last night, which, if you don't know, is a biopic about the life of Alfred Kinsey, who conducted the first major survey of human sexual activity in the United States. As a coda this morning I read this study in the Wash Post, on the high STD rate amongst teens who commit to maintaining their virginity, which often leads them to greater experimentation and riskier behavior.

One of my abortive posts this week was on a New Scientist article discussing the evolution of human altruism, which I thought would segue into a lament on the apparent lack of understanding of human behavior amongst people studying its evolution. People are a really startling evolutionary puzzle in many respects. We're first of all far too intelligent for the task at hand (mere survival), and much of our rich, complex social behavior makes very little sense from the dumb standpoint of selective advantage and fitness.

I'm often amazed that people studying this have such little appreciation for how much of what we do is there as social grease: we laugh, we fuck, we glower, we cry. Can you imagine such a thing? A fitness advantage that results from leaking salt water from the eyes and making strange howling noises. What does that imply? That communication of our emotional states to other humans is so important for us that even subtle signals become very meaningful. That a great part of our humanity lies in our expressivity, in revealing our inner selves to others. Think about that next time you're weeping.

As obvious is sex. Human beings are highly sexually abnormal creatures. They're better-equipped for it - a 500 pound gorilla has a 2 or 3 inch long penis, half the length of the average human male, who, for his body size, is one of the best-endowed creatures in the world. Human females are orgasmic, a completely unnecessary response for reproduction and almost unheard of amongst animals (if you've ever seen cats having sex, you know what I mean). Human females can be aroused at any time, not just during ovulation, even at the most paradoxical times (i.e. menstruation). Sex lasts much longer - most male animals only need to deposit some sperm, and the average mammalian encounter lasts no more than a minute; most humans would think they were being cheated if that were the case.

Our nearest living relative, the bonobo chimpanzee, has a similar problem. Bonobo society is built on sex. They have sex constantly, and they have varied, kinky sex. Oral sex, anal sex, homosexual sex, whatever. But they probably don't hold a candle to human sexual imaginations.

I've never understood why this doesn't scream out to people studying the evolution of human behavior. Why is sex so important to us, the ones who weep? The most intimate of acts, the conjoining of human flesh, isn't it obvious that it means more to us than simple fertilization? When we can laugh without marveling that we do so, can it really surprise us that we might take pleasure in each other simply for the sake of closeness, for comfort?

This is the way I've come to understand homosexuality in my mind. That particular sex act is described as deviant and unnatural because it clearly lacks procreative purpose. But human sex is NOT just about procreation; it's about social intimacy, a potent weapon in our arsenal of representation. Why not within sexes as well as between them? What then becomes "unnatural" is attempting to suppress that bit of us, that way of speaking. As well say we should not cry.