Katsuki is a man, and even if he did not realize that at 5 years old like all the famous transgender people he saw on the internet, he is still a man. He hasn't told anyone in his class that he is trans and its not to keep a secret but more to keep the other's mindsets as they are. He doesn't want pitty or to be treated like a fragile flower in a group of men. So he keeps it a secret. But to Bakugou's misery, his true disires and pains shine through when someone else gets what he has always wished for.

todoroki get disowned after telling his dad he's gay having no where to go todoroki wonders around town only to run into bakugou