Whipped cream

Thought I'd heard it all, but this one just tops it. Someone told me that women who have their period cannot whip cream, since the cream just won't get thick. Why? No answer, other than that women having their period "exert" something that makes the cream not thicken. What a bunch of bullshit! Makes me think of some religions that think women having their period are being "unclean". Or indeed when they used to burn witches, mainly because the burners were men and simply didn't understand women. May I remind this person that it is year 2007...and that some things have indeed changed the last 200 years...perhaps apart from the fact that men still do not understand women :)