I wanted to briefly weigh in here, because my son has two moms. It's been interesting watching him develop and grow (he's now 3.5) because we tried very hard not to put expectations on what he would like or force him to be anything he wasn't, and he naturally gravitated towards fire trucks and trains, and lately he's obsessed with all things dinosaurs. He's very physical and loves to roughhouse, run around, and get super dirty...I don't think he's ever met a puddle he doesn't like.
We have also noticed that he definitely craves male role models-not in place of his mommies, but in addition to. Luckily for him, my wife has two brothers and a brother-in-law who all adore my son, and my father and brother likewise offers him a ton of attention. He rarely goes more than a week or two without getting the chance to hang out with his grandpa or one of his uncles. And he's becoming quite handy for a 3.5 yr old, following around my brother in law anytime he's fixing things around the house, or insisting on "helping" me anytime something requires a tool. I will never forget the look of absolute joy on his face the day my brother in law and I replaced some railings on our deck, and my son saw a circular saw for the first time. I am convinced there's something primal and genetic about men and power tools! In any case, I don't think he loses anything by not having a father, because we've made very sure to engage him with our larger families and make sure he isn't isolated to just us and the dog.
At the same time, my son is a big cuddler and hugger. He's very sweet and empathetic, and is very focused on anything that involves helping or rescuing people. As long as his interests aren't actively harming him or anyone around him, we encourage him to be himself, and it's quite clear that he, at least right now, gravitates towards things that are stereotypical "male". Some of this is just who he is, some of it is probably what he absorbs from the world around him, but I think whether a boy is "feminized" has more to do with the expectations and societal pressures than anything innate. We know girls who are tomboys, we know boys who like My Little Pony, and we know boys who, like my son, have never met a siren/tool/destructive item they didn't like! Our attitude is that it's better to encourage a kid along their interests than force them into boxes.
(Plus if he grows up to be handy he can fix things around the house in our old age).