Maybe. I also have two brothers and he occasionally seems to forget that I'm a girl. I'm not sure how, I was a really girly kid and my brothers were holy terror ruffians.

Other times he's really "Eek! My little girl is growing up! T.T". Like when I turned 19 and casually pulled out a beer in front of him. Apparently it's a proud moment when your son does that, but heartbreaking when your daughter does.