Sexual Selection in Penises and Clitori

In species that do not use copulatory thrusting, especially insects, penises evolve more obvious tactile stimulators: nubs, spikes, ridges, curls, barbs, hooks, and flagella. Male insects often try to push each other off during copulation, so copulatory thrusting would risk disengagement. Better to lock the genitals together and have internal flagella to excite the female. With primates, it is not so common for male rivals to swarm over females knocking each other off. This allows couples a ...

 Babies Flirt

There are other reasons to think that even very young babies are especially tuned to people. Babies flirt. One of the great pleasures in life is to hold a three-month-old in your arms and talk absolute nonsense. "My, my, my," you hear your usually sane, responsible, professional voice saying, "you are a pretty bunny, aren't you, aren't you, aren't you, sweetums, aren't you a pretty bunny?" You raise your eyebrows and purse your mouth and make ridiculous faces. But the even more striking thing...

 Male and Female Differences on Pornography

Hard porn, which depicts actual acts of sex, is almost invariably about the gratification of male lust by willing, easily aroused, varied, multiple, and physically attractive women (or men, in the case of gay porn). It is virtually devoid of context, plot, flirtation, courtship, and even much foreplay. There are no encumbering relationships, and the coupling duo are usually depicted as strangers. When two scientists showed heterosexual students pornographic films and measured their arousal by...

 Orgasms and Sperm Retention

t. Baker and Bellis discovered that the amount of sperm that is retained in a woman's vagina after sex varies according to whether she had an orgasm and when. It also depends on how long it was since she last had sex: The longer the period, the more sperm stays in, unless she has what the scientists call "a noncopulatory orgasm" in between. So far none of this contained great surprises; these facts were unknown before Baker and Bellis did their work (which consisted of samples collected by ...

 Ways to Understand Male Sexuality

There are five ways to find out. One is to study modern people directly and describe what they do as the human mating system The answer is usually monogamous marriage. A second way is to look at human history and divine from our past what sexual arrangements are typical of our species. But history teaches a dismal lesson: A common arrangement from our past was that rich and powerful men enslaved concubines in large harems. A third way is to look at people living in simple societies with Ston...