"We may not be able to make out the modern hunter behind his PC or his cell phone. We may not detect the dominance struggles and status competitions that hide in sophisticated organization charts. We may even find it tough to spot the warrior in a high-tech, demasculinzed army. But it is impossible not to see the primitive origins of the modern man on the hunt for sex.

Throughout the mammalian, primate, and hominid eons, during the millions of years of human evolution, the deeply entrenched genetic program for a male has been to plant his seed wide, plant it often, and plant it quickly. Until recently life on earth was a brutal, competitive struggle, a place where feeble infants were slaughtered, weak children fell by the wayside, and relatively few offspring lived to maturity. Quantity, not quality, won the genetic future. Place a lot of bets so that a few survive—and hurry, because you may not be around tomorrow. Natural selection made shoot-from-between-the-hips a sexual winner for males. Besides, it wasn't you getting pregnant.

The resulting sensitivity among men toward shallower sexual arousal and a bent for immediate gratification is a universal phenomenon. In every culture males demonstrate more compulsion, more aggression, and less discrimination when it has anything to do with sex. Nature did not favor the sensitive male. If he dallied, a man's potency might falter, or maybe he got killed. Numerous fleeting, nimble-footed forays were the way to genetic immortality—or at least to a good time.

Ever on the lookout for young healthy females, ancestral males developed a sexual approach designed for breadth, not depth. Rapid visuals were in; long interviews were out. The "quickie" was born before the savanna. These dynamics help explain the persistent male interest in pornography. Crude, in-your-face, anonymous female nudity sends male blood rushing. Pornography may be failed imagination, or just brute instinct given shape. Either way, it appeals directly to the testosterone addled hunter who is alive and often pumped in today's man.

Skin-deep male arousal is the force that propels a million girlie magazines, a thousand strip joints, and pervasive sexual imagery throughout most cultures. It is why more than $20 billion is spent annually on "adult" videos, and more than $10 billion on escort services. It is why prostitution and the sex trade claim staggering amounts of our gross national product. Adult Video News, the industry "bible," reports eleven thousand new porn titles in 2000, versus four hundred out of Hollywood. Who rents them? About 70 percent are lone males and 20 percent are men with women. Gay men together rent 7 percent. One percent is rented by women with women, and just 2 percent by women alone.

According to Nielsen NetRatings, about a quarter of the Web-connected population checks out porn sites at home, one in six do at the office. The superficial sexual trigger, honed in the forest and out on the savanna, is why men still duck out of chat rooms and keep going back to the superbabes and vixens. Commenting on the dot-com shakeout, Hustler's marketing director told The Los Angeles Times: "The sex industry really isn't affected by the markets. Sex always sells." The male modem is always online.

Males are the all-terrain vehicles of sexual insecurity. It is a standard deficiency built into masculinity's frame, engine, and dashboard. Men are not grounded by a womb and its responsibilities; they are not tied to lunar cycles. Scratching itches a lot of the time, they are more like motorized erections looking for a dark, damp receptacle. An erect penis has no I.Q. Logic may be its enemy.

Also lying in wait in most males is a sexual eccentric. The homeless male drifter and the Nobel laureate are equally at risk to succumb to overcharged or misplaced testosterone bolts. Archbishop to rock star, through sexual deviance they risk the loss of exalted position. They may even risk their lives. Unable to control themselves, deviant males of high station endure wide public shame. We are unlikely to read of female movie stars buying sex at three in the morning in a sleazy red light district. No British baroness will be asphyxiated in a masturbatory frenzy by hanging herself in male leggings and an athletic supporter. Men, it seems, are the sexual jokers. The problem is that they make up half the deck.