Have a read of this... rather interesting ...
http://www.msnbc.msn.com/id/20466219/
but as suggested on the thread (men are from mars, women from venus) it might just come down to instinctive differences. Maybe. Personally I am interested in Mars and Venus and everything else in the universe and beyond (if there is a beyond that is).
Gendered interests are often also fostered by the same gender parent (ie. 'traditional' interests). Social and peer 'norms' and expectations can also influence a child or youths interest.
My dad was a science teacher and I have always enjoyed science, knowing how things work and why they work that way...perhaps my childhood influences have something to do with it.
Also adult resposibilities of females (eg. rearing kids, household stuff) can make scientific hobbies prohibitive in some cases or stages of life. This scenario is again rather traditionalist.
Cheers, Kerrie