Slate columnist makes a persuasive case for MTV’s show on virginity loss, saying it’s about time someone tackled the subject honestly and even-handedly. Because we ain’t getting that in the movies:
If it’s the girl who’s having sex for the first time, forget gross-out humor. The act is now freighted with consequence. In Juno, a girl has sex and gets pregnant. In Saved!, same. In Fast Times at Ridgemont High, a girl has sex and then more sex and gets pregnant. In Cruel Intentions, a girl has sex and gets betrayed. As a Yahoo! Shine writer pointed out, when boys have sex it’s typically the culmination of a movie’s plot, whereas for girls, sex is where the movie’s storyline begins, unspooling into lies, tough choices, and shattered relationships.
Mostly Modern Media 
It’s another example of the very real double standard, that having sex for a young man is an accomplishment, and having sex makes a young woman a whore who must be punished.