Research/articles (hwk help!)

[ryntha-doghare.livejournal.com]

So, for my Psychology class I've been set a 5 minute presentation on whether Gender is environmentally or genetically determined. (I actually requested Gender Studies, as opposed to, say, Crime...for obvious reasons of personal interest :P)
So I was wondering if any of you could help me out by linking to some interesting articles or pieces of research that either suggest gender (and in a more general way, 'gender (stereotyped) behaviour') is/is not determined by environmental influence, or is/is not determined by genetics, that you know of? Thanks in advance!

ETA: Thanks everyone for all the help! I just hope I can do it justice. :)