I think humor is a defense mechanism that happens to women when they become mothers. Not that non-maternal women aren't funny--they are--but that there is an almost tangible element of self-preservation in the humor of women with children. It's that "laugh to keep from crying" thing, most likely.
Now, PLEASE READ THIS. And make sure that 1.) You're not drinking anything while you read it, and 2.) You don't need to pee before you read this.
That is all.