In a Rolling Stone interview from 1979, Johnny Carson, host of "Tonight" and the most important gatekeeper in comedy for decades, gave his take on female comics.
"The ones that try sometimes are a little aggressive for my taste," he said. "I'll take it from a guy, but from women, sometimes, it just doesn't fit too well."
That attitude is certainly durable - see Christopher Hitchens's uncharacteristically dumb 2007 column for Vanity Fair, "Why Women Aren't Funny" - but it no longer holds sway. Comics like Joan Rivers, Roseanne Barr and Sandra Bernhard were trailblazers, but if you had to pinpoint one joke as a breakthrough for this new generation of female comedians, it might be this one: "I was raped by a doctor, which is so bittersweet for a Jewish girl."