Caving Outfit

Our 12 year old son loves dressing like his twin sister. My fault for dressing them alike until school age.?
Three weeks ago, for their 12th birthday, I took them shopping, got them a couple of matching outfits, and had their ears pierced. I bought Jenny two training bras, and after a 40 minute argument, bought matching bras for Jimmy saying he could only wear the bras at home.
We’ve always let them spend their summer dressing identically and after three weeks of fighting I caved in.
How do I put this Genie back in the bottle?
Oh, No, They are children growing
Leave then doing what they wanna do, (if it´s safe)
If he wants to dress like a girl… Is his desire
Later On in life he will realize if is wrong or right if he wants
And you shall not argue about it because he will ignore you if you do it
Leave them live life
Dino Crisis Death Scene No Redout: T-Rex 1 (Cave Costume)