Hi, Guys!
As you know, people who don't like us find various strategies for opposing transgender rights. One of the most common ones is to deny that ->-bleeped-<- exists. There are various ways of doing this. E.g., we're not really trans. We're just screwed up because of the way our parents raised us. If we could find the right shrink, he'd "unscrew us up", and then we wouldn't be trans any more.
Another way of denying the existence of ->-bleeped-<- is one I've heard quite often from certain cisgender women, former tomboys. They'll tell you all about their rough-and-tumble days when they were little: "I dressed like a boy, I played with the boys, I really wanted to be a boy."
Inevitably, though, they reach puberty, the hormones kick in, and they start behaving like girls. And they always seem to be fairly embarrassed by their former tomboy ways and days. But they insist that boyish behavior is just a phase that "girls" should grow out of.
Now how exactly to explain the difference between a transboy and a tomboy? Going on my own experience, I could explain that ->-bleeped-<- isn't a phase—unless you want to regard birth to death as a phase. And I could talk about the difference between gender identity and gender expression.
But in a way, this is a question that we girls aren't equipped to answer because we never have to. We don't have cisguys telling us, "When I was little, I used to wear dresses and play with dolls and have tea parties with the neighbor girls, but I eventually grew out of it." If there are guys like that (and who knows, maybe there are), they won't admit it now.
So I was wondering if some of you guys have your own way of addressing this question. What specifically would you say to a former tomboy who's claiming that there's really no such thing as a transboy?