I have to admit that after all these years, sex is still a mystery to me. Especially human sex. Not that I've tried any other kind.
    What I'm trying to say here is that for all that biologists and other researchers have learned about human sexuality, there are still some fundamental mysteries. A new study published this week deepens one of them. Why is that in women, as opposed to, oh, I don't know, let's say, baboons, the estrus cycle is concealed?
     Contrary to what certain poets and humorists say, there is no "mating season" for humans. Stranger still, in any given month there is no obvious way for a man to tell if a woman is ready to conceive. So, humans have sex on a regular basis year-round -- at least until they get married. (Settle down, only kidding.)
    This is in stark contrast to many other critters -- including most of our primate relatives. If you're a male baboon, knowing when to mate is no problem. Female baboons in estrus practically put billboards on their rears saying "Get It Here!"
    Not so with women. However, according to Dr. Jon Maner, lead researcher in the Florida State study, the scent of a woman in heat is enough to send a man's testosterone on the boil. He and his colleagues got women to wear T-shirts to bed during various phases of their monthly cycle. They then had men sniff the T-shirts, along with some that hadn't been worn at all. The men who sniffed the T-shirts of fertile women experienced a significant rise in their testosterone level.
    Maner calls this a smoking gun. Together with other evidence of subtle female estrus signaling, he says it clearly demonstrates that women guide men's sexual behavior toward intercourse at the time likeliest to result in pregnancy. (You can hear my interview with him online this Saturday at 8:30 a.m. CST on kzum.org.)
    Maybe. But other studies of human sexuality don't support the conclusion that increased testosterone correlates with well-timed intercourse.
    Besides, the whole business of concealed estrus seems strange. Why so coy? Some researchers have speculated that women evolved to disguise their estrus so that they could keep one or more men hanging around the old cave  at all times.
    Again, maybe. But then men evolved Moe's Tavern. Move, countermove.
    Anyway, if women are signaling men via their scent, I think this may fall into the category of Nature's Mistakes. Just as women persist in the misguided idea that men notice their shoes, choosing scents for signals seems deeply mistaken. Generally, men are oblivious to the smell of old socks, spilled beer, and wet dogs. Why should they notice something so subtle?
    Or perhaps it's quite ingenious. After all, if a woman wants to manipulate a man, the very best way to do it is without his ever knowing it happened. And if it all ends happily in sex, who's to complain?
   

                                                                 *      *       *

 If you like this, pass it on. You may also wish to read my religion blog at The Huffington Post : http://www.huffingtonpost.com/clay-naff