On the subject of girls, math, and people sending unintentional messages

Girls are, of course, less likely to be given mathy toys like blocks or legos as presents. (Boys are less likely to get books. I'm sure that all these gift-givers know the children intimately and are only following the kids' interests, interests which were formed devoid of any outside input, straight out of the ether.)

At any rate, you've probably already seen these two videos on Lego's pointlessly gendered advertising, but just in case, there you go! (They even have transcriptions.)

And here's a bonus lego-related entry on... well, influencing how other people build with them, basically.