Surfing around, I've found advice board postings where people ask what to do about their teenage son who they caught wearing lingerie or something. One suggestion that seems common is to buy him something similar so he doesn't have to steal from his sister or mom, and see what happens. The rationale is that he'll get what he wants, and be satisfied with experimenting with it.
So, what if...?
Man, I wish. So when my mother found my stash (which consisted of her bathing suit and leotard and tights) she could have gotten this advice. She would have given me her bathing suit that I had stolen, and which had really gotten me most interested in wearing girl clothes. Or she would have bought me a new one. I would have been utterly mortified, even though she would have given it to me secretly. But I would totally have worn it.
Now, with a signal that it's ok, I'd have become curious about other things. I was already fantasizing about bikinis and lingerie. I would have sheepishly asked for a bikini eventually. She would initially refuse, but she'd feel bad, and give in, and buy me something modest. I'd have been disappointed slightly, but hey, it's still a girlie bikini!
I'd wear that one a lot, then ask for a skimpier bikini. This time, I show her a specific one. She gets it for me, and asks if I want to wear underwear, too, full time, if I want to be a girl. I of course refuse, clinging to my maleness. I think about it while wanking in my new string bikini, and regret my answer.
After a while of feeding these fantasies, I would admit that I'd love to wear panties. So now we'd go together to get panties. Mostly modest ones, cuz she'd try to discourage me. But I'd push the limit as much as I dare. I'd now be wearing panties all the time, and be very confused about what this means as far as my own sexuality. Given how much I love it, I'd surely conclude that yes, I'm a girl in a boy's body, and come out as such. Now all of a sudden, I'm in therapy, and wearing skirts and dresses.
Given how permissive therapists can be about this stuff, they'd encourage me to drop all attachment to my maleness, and embrace my feminine urges. I'd start hormone therapy, and grow boobs and get all girlified. I'd be wanking almost constantly now.
Eventually, I'd get the surgery, and become a girl. Luckily, I started in puberty, before it was too late, so I look passable.