My wife was asked that question ("are you married, do you have kids?") in an interview with a tiny company 30 years ago. She attributed it to ignorance and replied "That's not a legal question to ask". The interviewer apologized profusely and he hired her. He turned out to be a really nice person who was unaware of what was out-of-bounds to ask in an interview. But that was 30 years ago, people should know better now.