Need some non-biased science-based sources!!!

Okay! So my boyfriend is debating with me. And I'm actually really mad and upset. Like if I can't convince him, and teach him, I'll leave. These things are very big issues to me and I hold them dear.

He believes:

* You MUST have gender dysphoria to be transgender

* If you don't have gender dysphoria and you call yourself trans, you're trying to get attention.

* There are only 2 genders. This one really struck me as one of his friends is agender... and he says it's for attention

And normally I'm very good at explaining myself but he is a "science" and "hard facts" person. So I need some really good links I can give him. And if he doesn't change his mind I'll leave because these are beliefs I believe in, and it's about being an accepting human being. I can't be with someone who's not accepting. So please help 😊