If your friend has published research then you can name him. Who is this?
Hubbard was unremarkable as a young male weightlifter but after transition to an old female has a world championship medal and was on track to win Commonwealth gold. That makes it look to me that she has acquired an advantage.
Val Adams is a very large and powerful woman and one of the all time greats of women's shot put. But a middle of the road male shot putter would beat her easily. Men throw a shot *double* the weight of the women and they throw it further. All it takes is an average male shot putter to transition to female and all women's shot records will be beaten. Is that fair? I don't think so.
I didn't mention his name because he is retired and is currently undergoing medical treatment so I can't ask his permission. He is well-known in his field and has published many research papers around the world but I don't feel comfortable mentioning him in this context without asking him first. Either take my word for it or don't. I don't care.
Edit: I forgot to respond to your second part. Have you taken an average male shot putter and transitioned him to female and seen her beat all women's shot records? Until you have, you are just speculating. Don't try to present it as established fact. It is simply unsubstantiated opinion, like most of the other posts here.