If you're a female celebrity and you haven't gone girl-on-girl before a crowd of roaring, adoring males, you're probably gay. Last night, Sandra kissed Scarlett as revenge on Jesse. How did lesbian kisses become the ultimate mainstream display of hetero-desirability?

Looking good is no longer the ultimate revenge, nor is dating someone younger, taller, and better looking. The ultimate post-break-up revenge for a heterosexual lady is to make out with another lady, preferably on a stage. Here's Sandra Bullock doing it at the MTV Movie Awards:

Back in 1995, "I Kissed a Girl" was a song by a lesbian folk singer about being gay. Eight years later, Madonna caused a media shitstorm by kissing the resolutely straight Britney Spears and Christina Aguilera on an MTV stage. Seven years after that, a former Christian rocker turned "I Kissed a Girl" into a anthem of straight girl titillation. Now America's middle-aged sweetheart is locking lips with ladies on another MTV stage to prove she's as hetero-lovable as ever. And tween queen Miley Cyrus says the girl-on-girl near-kisses in her choreography are "nothing" and shouldn't imply gayness at all.

Plenty of ink has been spilled about what straight girls kissing other girls means for gays, bisexuals, feminism, sex generally, and sexy Maxim spreads specifically. (Only the last one has a conclusive answer.) Let us now consider what straight lesbian kisses mean individually:

Got more? Add them in comments.

[Photos via X-17, Splash, and Getty]