I do agree that focus on genitalia is generally unnecessary and unwelcome. In this case though we are discussing trans-women fearing people with penises raping

I do agree that focus on genitalia is generally unnecessary and unwelcome. In this case though we are discussing trans-women fearing people with penises raping them in men's prisons, and cis-women fearing people with penises raping them in women's prisons. In this context, if a trans-woman doesn't have a penis then this fear is unfounded and they should be housed with cis-women. If a trans-woman does have a penis, then I think this fear is reasonable (after all, that is what trans-women are escaping when they leave men's prisons). Basically, this is one of the few cases where discussing genitalia is relevant.