not that many. But at the same time I don't know of any males claiming to be females (on freenode).
You have disrespected them (and potentially males) by claiming that all who claim to be female on IRC are in fact male, and that we should be aware that they are lying. I have no such knowledge that they are... and it simply doesn't matter to me if they are. But I prefer to believe people are honest, and if someone claiming to be a female on IRC is actually a male, it probably won't matter much to me, because I'm not on IRC to date in the first place.
note: the actual male to female ratio is irrelevant.