When asked a question that appears to be illegal, it's much better to respond in a professional manner than directly confronting the hiring manager about breaking the law. In other words, answer the question as if it was asked correctly. If the interviewer asks about your age, simply talk about what's been learned throughout your working career. An illegal interview question might also signal the possibility of a hostile work environment. Companies should know what's appropriate to ask a candidate during an interview. If they don't, then chances are they might be allowing other forms of inappropriate behavior in the workplace.