Yeah, absolutely - clearly people should be able to choose what they want to do. The problem would be if you wanted to become a doctor but were told by everyone

Yeah, absolutely - clearly people should be able to choose what they want to do. The problem would be if you wanted to become a doctor but were told by everyone that you shouldn't be (because, you're a man, or a woman, or black or white or yellow or whatever it happens to be). You might still do it (and let's hope so, we generally need more doctors) but it would be harder for you and thus statistically you'd be much less likely to do it. That would be society's loss - especially if you ended up shampooing dogs :-)