In the wake of 15-year-old Miley Cyrus posing in makeup and not much else for Vanity Fair, Hugh Hefner has stated that he would like to see Miley pose naked for Playboy-when she turns 18. I believe Hefner's offer, albeit cloaked in the disclaimer that Miley has to be legal to strip for him, may herald a challenge to the current age of sexual consent-which is between 16 and 18 in almost all states, lower only in South Carolina (and only when the sexual partners are both young).

What Hefner chose to do was to express being sexually attracted to an underage girl. He knows that he is perceived as freeing American men to express their sexuality. In this case, he is presumably leading the way in suggesting that men ought to feel free to direct their sexual fantasies toward 15-year-olds-bemoaning, perhaps, the fact that they will have to impatiently wait to get them out of their clothes.

I don't know that Hefner would have felt restrained were Miley just 14. Maybe even a fetching 13 After all, he wasn't the one who suggested that Miley get almost-naked for Vanity Fair. And she certainly didn't look ill-at-ease with her sexuality in that magazine. She looked seductive. Disney didn't recoil in horror. Miley is Money. The show goes on, no matter how much she chooses to show. That seeming comfort with sexuality-at 15, or less-is part of the issue here. We know that many 15-year-olds are sexually active. According to some data, one in three ninth graders has had sexual intercourse.

The age of puberty has been steadily declining.

Hefner's comment is, nonetheless, a kind of gauntlet thrown down to the legal age of consent_ He isn't in ninth grade. He's an adult man. He is openly attracted to an underage girl. And he doesn't seem worried about saying so.

This potential chapter in the story of the sexual revolution wasn't written by Hefner, though. Signs that Americans are rethinking age-appropriate sexual activity are everywhere.

After all, the American public embraced, rather than shunned, Jamie Lynn Spears after her pregnancy. Untold millions of magazines that showcase her new home and the birth of her daughter and her daughter's first birthday will be sold.

Will the fact that she is an unwed, pregnant 16-year-old with more media attention than ever suggest to young girls around America that they, too, can start their families sooner, rather than later? Will they wonder what have they been waiting for?

Only time will tell. But one thing is clear: The time that was once allowed teenaged girls to slowly grow into being sensual, to play at adulthood without being treated by older men as adults, is under assault. And you partly have the media to thank for that: The unlikely and powerful alliance of Disney, Vanity Fair and Playboy.

Keith Ablow, M.D. is a psychiatrist, FOX News contributor and the founder of www.LivingtheTruth.com

Dr. Keith Ablow is a psychiatrist and member of the Fox News Medical A-Team.