Halah, I am EXACTLY like you with the feminism....I was hellbent on not having a single Barbie or Disney princess or even an Easy Bake Oven in my house. My girls were to be raised in a manner that never let them feel that they had to be this or do this because they were female. Well. They figured out about Barbies and Princesses from preschool. And they got some, and they play with them just like any boy plays with his trucks and Spiderman and whatnot....but my youngest also likes cars a lot. They both love to cook, but we do that as a family, with DH...they don't think it is a "woman's job." I guess my point is that your child will love what they do, of course, BUT your influence, the way you teach them about the world around them (like me saying, "You know, real people don't have bodies like this. But, this is the way Barbies have been made for years. Funny, huh?") makes a huge difference! And I don't mean that in a brainwashing kind of way, more of a teaching them the way the world really is way.
I know how you girls feel, though, because I am the opposite, no boys, just girls....which I never thought I'd have. I get nervous that if I had a boy that I wouldn't want to play truck and boy stuff with them, because I love playing with my girls and understand their interests. But, let me say, I am sure that if you have girls in there, they will LOVE having big brothers so much....how protected they will feel. Not to mention, they will be the apple of eveyone's eye in a postive way, and learn a lot about men before they venture out into the harsh world of dating! Just don't be nervous, you will be the same awesome mom to this kid, girl or boy, that you already are. You all will navigate the world of Barbies and such with ease, I promise!