What if it simply means that, on average, there are certain characteristics more commonly found in boys (and others more commonly found in girls)? It doesn’t mean that all boys share them, nor that no girl has them. And it certainly doesn’t mean that if a boy doesn’t have them all, or even if he doesn’t have any, he’s not a real boy.
I don’t think we, including boys and girls, are so fragile. Besides, if a boy is very shy and bookish, he already knows, without having read anything about what’s typical, that he’s different from the average boy—and he’ll be OK. He’ll learn to cope. Maybe he’ll even develop, as a result, a stronger character, a thoughtful disposition, a keener understanding of human nature. Or maybe not (but he’ll still do just fine). The point is that we all have our struggles and we all learn, for the most part, to manage—excepting truly traumatic experiences, of course. This doesn’t mean that then we should just tolerate meanness, bullying, bigotry, etc. Not at all. It’s just that there’s no need to be walking on eggshells all the time.