Young Hollywood stars seem to have hit a new low. Why are they suddenly so oversexed, so determined to show all, so proud of parading around naked?

One answer: Because they want to.

Another: survival.

Survival of the fittest — and the sexiest. Being a dirty girl seems to be the newest movement in our pop culture evolution, as many of the hottest stars of the moment are upping the sexual ante by taking the Marilyn Monroe sex kitten idea to new, lower and raunchier levels. And a debate has erupted over this new "soft porn" normal, not just among pundits and parents, but within the industry itself.

"Every pop star wants to look sexy," says Paris Hilton, 32, whose new single and video, Good Time, features her rolling around poolside in a slinky swimsuit, arching her back and rubbing her body. It was her vision entirely, she says. "I wanted to write something that was talking about having a good time, having fun, not caring what anyone thinks and living your life."