I doubt "science" has an answer for that question. But "science" certainly can tell the difference between a him and a her. It is actually really easy.He is not a she. Does the left know anything about science?Why is the logical conclusion not to respect the right of women to expect privacy and safety while using the bathroom?
Your privacy and security aren't in jeopardy by allowing trans women to pee in women's restrooms. Hers would be if she was forced to use the men's restroom.
Okay Dr Imbecile, what does science recommend when dealing with trans people?
Doctors who gave studied it do. What do they recommend, Einstein?
Dr. Hossfly recommends mental health counselling.