Exactly. I've always been told in hiring/legal meetings that it's ok if the candidate voluntarily discloses information about their religion/race/family status,

Exactly. I've always been told in hiring/legal meetings that it's ok if the candidate voluntarily discloses information about their religion/race/family status, you just can't go looking for it, and you probably shouldn't follow up about it. Essentially, as long as your question has a reasonable answer that doesn't involve bringing up any of the protected attributes, it's fine.