for the ‘imamother’ site, you havta be a Jewish female & married to join their site.. you are asked to fill out a questionnaire at registration so that they can ‘verify’ (?) that you are so. I would imagine it’s not foolproof, but…
It’s not foolproof at all. Any married man who knows hilchos taharas hamishpacha could answer those questions, and anyone else could use google to figure it out.