There's a moment in nearly every decent episode of The Simpsons when Homer and his alcoholic pal Barney are sitting around Moe's Tavern and the latter lets out a belch so powerful that the wind causes his lips to flap like two pieces of raw bacon draped over a Vornado. This is funny for two reasons: (1) Someone is unleashing a monster burp on national television and (2) that someone is a man.

Yes, women are born with the ability to belch with the best of them, as is regularly proved by little sisters the world over. But as any good sitcom writer (or older brother) can tell you, such behavior is rarely amusing to anyone other than the burper herself—and it gets less amusing the older she gets. Also not funny: When a woman lets one rip. Or hocks a loogie.

It takes but a brief stroll through the pages of Us Weekly to find evidence that we're on the verge of some kind of neo-cavewoman epidemic. There's comedian Sarah Silverman—essentially famous for being a female version of Andrew Dice Clay—pretending to crap her pants in a farting competition on her Comedy Central sitcom.

There's America's Next Top Model winner Adrianne Curry burping intelligible sentences on VH1's My Fair Brady. There's Jessica Simpson bragging in Cosmopolitan "I think it's funny when I clear out a room because I farted." And then there's wannabe punk-rocker Avril Lavigne, who may not dress like a dude anymore but was acting like one when she fired saliva bullets at two different photographers during a 48-hour period in 2006.

"Celebrities are less concerned with trying to perpetuate this false ideal of a perfect image," says Perez Hilton, the celebrity-gossip blogger, by way of explaining the emergence of these bog beasts. "So what were once these perfect superstars are now seen as regular people."

Regular people? More like frat boys channeling their inner Jackass. Actress Eva Mendes, reminiscing once about a 2005 trip to Nepal during which she shared a hotel room with Cameron Diaz, ruined what could have been the greatest male fantasy since Denise Richards and Neve Campbell got it on in Wild Things by revealing that "Cameron is a big old belcher, but I can't belch." She added, "One night I had a heavy dinner, so I combated her belching with something I could do. We were in side-by-side beds—her disgusting bodily function versus mine. It was an Eva-Cameron fart-belch-off!"

Cameron Diaz showing off her burping skills

This knowledge makes it impossible for any man to enjoy watching 2 Fast 2 Furious ever again. It's hardly surprising that Mendes' roommate that night was Diaz; the actress who is the voice of Princess Fiona in the Shrek franchise has become the poster child for this whole foul trend. Type her name into any search engine and you'll find reports of her grodiness: multiple references to her theory about how everything in life eventually comes back to "poo," the clip of her proudly burping on a British talk show . . . the list goes on. The cause of her and Justin Timberlake's breakup was never reported. Best guess: He dumped her because she wouldn't stop passing gas.