Why are girls not funny?

[scotty34]

When asked who can consistently make me laugh, I don't think I can include a single girl on the list. There is an endless list of guys whether they be comedians, actors, or just friends of mine. Examples Will Farrell, Jerry Seinfeld, Chris Rock, Peter Griffin... Even as noted in the most funny Simpsons characters thread, the answers did not contain any females and they topped most lists in least funny characters.

I don't understand why, but for some reason girls just are not (intentionally) funny. I don't remember which show this was from, but this sums up female comedy quite well

A female comedian is on stage

"So, I had my period today" (short pause, then audience laughs)

Agree/Disagree? Can you name some funny females?