"A trans woman's biology is a female biology" is just a statement I cannot agree with at all. One of my best friends growing up was a guy I'll call Adam. In high school Adam was an incredible athlete (he was a runner and swimmer) and held a lot of county records and was the third fastest at the 400m hurdles in the state. Adam came out as trans around his 21st birthday and now lives a woman I'll call Alice. Alice is a trans woman. The idea that her biology is that of a person born with two X chromosomes and a vagina is a little ridiculous to me. I see Alice as a woman today because that's what she wants and it doesn't make a difference to our friendship however I know Alice has a penis and spent 90% of her life living as a boy/man. FWIW, she and I have talked a lot about this and shares my views. In fact my views on the matter are largely influenced by her perspective on it.