Michele Bachmann whines about how Newt Gingrich treats her in debate.
While she stops short of accusing him of sexism, she certainly implies it.
But if the gender bias card is now face-up on the table, it's not Gingrich who played it, it's Bachmann (and her supporters, e.g. Michael Steele tweeting "you go, girl").
Bachmann has a habit of getting her facts wrong (not just with Gingrich -- see e.g. her exchange with Ron Paul concerning Iran's nuclear capabilities) and, in some cases, apparently just making shit up and attributing it to unidentified supporters who somehow manage to buttonhole her in public without anyone else hearing, then disappear never to be seen again (she's pulled that one out of the hat with both Rick Perry and Newt Gingrich).
If anything, her opponents have probably cut her more slack on that kind of thing than a male opponent would have received.
There's more to being a serious candidate than repeatedly claiming that you're a serious candidate. If you want to be one of the boys, wear a cup and take the kicks like one instead of whining about it. Or, to put it a different way, if Bachmann doesn't want her opponents to dismiss her as a stupid bitch, she should stop playing one on TV.