Ok so here’s how it works
Dads with daughters: Women’s restroom.
Moms with daughters: Women’s restroom.
Dads with sons: Men’s restrooms.
Mothers with sons: Women’s restroom.
Hope that helps.
If as a man you ask to see your girlfriends’s pad as proof that she’s really on her periods, understand that you don’t respect consent and that you're a rapist.