How do you stop him? There’s a variety of ways – handcuff him, cut his arms off, cut his legs off, remove every sharp object from the house, etc. But all of these things ignore the real question: Why do you want to stop him?
I suspect you have some homophobia (or maybe transphobia) going on. Or maybe some toxic/fragile masculinity. In any case, your son is a human being and as such, has bodily autonomy. This means that he gets to make the decisions about what he does with his own body. Not you. He isn’t hurting himself (your hurt feelings don’t count). He isn’t endangering himself – unless you or your home environment is so toxic that he is in danger of being harassed or assaulted for having clean-shaven legs (in which case, the real problem isn’t with him, but with you).
Your boy shaved his legs? You keep your mouth shut unless you have something nice to say (and no sarcasm). And you thank your lucky stars that this is your biggest worry with your 15-year-old child.
Take him clothes shopping and buy him all the dresses he wants. Celebrate that you have a child who is comfortable enough in his own skin to step outside of social boundaries to express himself. Thank your lucky stars that your child trusts you enough to share this with you!
“Leave them (the transgender person) alone. Feel however you feel, but you have no right to approach or make them feel uncomfortable. Get over yourself.”