As a cis woman, who trains in mixed martial arts, with both trans women and men, I have to disagree with. you here. Yes, people assigned male at birth often have more muscle mass, but it tends to wane and even disappear after HRT. I haven't seen advantages in my trans sisters training partners. I mean I know there is more to this argument, anecdotal evidence isn't proof, but as woman, who trains with other cis women as well as trans women and trans men, it really hasn't been an issue.