BRONX breeze tosses her pigtails as she glides down a busy thoroughfare that carries her into the latticework shadows of subway tracks overhead. Dressed in a sleeveless denim jacket and tight flared pants, the young woman draws shouts of obscenities as she weaves between an ill-tempered pimp and a group of barely dressed prostitutes.

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She jumps the curb and turns into a rundown city park after pedaling her dirt bike around a surly homeless man and a tart-tongued street vendor. Racing up a ramp and then vaulting high into the air, she spins in two 360-degree twists before landing in the low grass with a clank, to the cheers of unseen spectators.

It's all in the digital day of a nearly photorealistic trick biker in BMX XXX, a video game from Acclaim Entertainment scheduled for release this month. But don't expect to find any supersonic hedgehogs or heroic Jedi knights lurking in this interactive fare, because this one is strictly not for the kiddies.

BMX XXX is rated M for mature (for players age 17 and older). And from its title to its marketing, the game flaunts its aggressive sexuality, salty language and off-color sight gags.

In an advertising campaign at the game's Web site (bmxxxx.com), Acclaim promises to "Keep It Dirty," using a double-entendre that could just as easily refer to virtual dirt biking as to features like having the computer-generated young woman ride topless or permitting players to follow her to a back alley strip club to watch videos of real women stripping.

Sexuality is the newest supercharged element in a small but significant wave of video games that is soon to reach American store shelves. While the sex play in these games tends to be more suggestive than explicit, what is striking, even startling, is how it has moved from the periphery to center stage.

Advances in technology, particularly the computing power that can now be harnessed to generate realistic animation, is helping to drive the trend. But the shift has even more to do with changing tastes and standards in mass entertainment in an age that is less "American Graffiti" than "American Pie."

"Part of it is marketing," said Vinnie Longobardo, senior vice president for programming at G4, a new cable television network dedicated to video games. "How do you distinguish your game from the pack?''

On the other hand, Mr. Longobardo said, revving up the sexual content in new games might be "a cover-up for not having anything completely innovative and new on the game-play side."

Whatever the game makers' inspiration, or lack of it, some retailers are already making it clear that a line has been crossed. Several have announced that they will not be selling BMX XXX.

Sex, of course, has been seeping into video games for years, from the crudely made hard-core offerings sold online and in adult bookstores to far less explicit permutations like the digital dating rituals in hot tubs in the Sims series. There has long been Lara Croft, the original video vixen with impossible proportions. And in Japan, highly sexual video games have long been popular with both young men and women.

As a result of increases in the number of frames per second, the polygon counts in graphics and sheer processing power, however, characters in computer-animated cartoons are beginning to look and move as real people do - sexy real people. That has disturbed some while delighting others.

Some game developers say that the heightened sexual element of some of the new games is a response to the increasing age of video game players, who are mostly male and less inclined to view video games as children's toys. Their tastes in games simply parallel their tastes in movies, those developers argue.

Consequently, more sexually charged video games will soon be available for play on the most popular game consoles, including Sony's PlayStation 2, Microsoft's Xbox and Nintendo's GameCube.

Aside from BMX XXX, there is Dead or Alive: Xtreme Beach Volleyball, a new installment in a hit game series by Tecmo, a Japanese game developer. The game, due next month, features voluptuous heroines who preen, sun themselves and play high-stakes volleyball in skimpy bathing suits on a tropical island.

"The eye candy in the game characters looks beautiful," said Tony Tarpey, a marketing manager for Tecmo. "Dead or Alive has always been known for sexy characters."