No idea. It seems to me that Remus gets preggers a lot, too, though, and that one I can see. I mean, he's obsessed with chocolate, he hates to see people unhappy, he's got these uncannily "sixth-sense" modes of emoting (WHY did he hug Sirius in the Shrieking Shack when there was no real proof of his innocence yet?), and he turns into a real bitch once a month.

You can't tell me those are male habits.