BEST ANSWER: Under the ever-present threat of lawsuits, most interviewers are well aware of these taboos. Yet you may encounter, usually on a second or third interview, a senior executive who doesn’t interview much and forgets he can’t ask such questions.
You can handle an illegal question in several ways. First, you can assert your legal right not to answer. But this will frighten or embarrass your interviewer and destroy any rapport you had.
Second, you could swallow your concerns over privacy and answer the question straight forwardly if you feel the answer could help you. For example, your interviewer, a devout Baptist, recognizes you from church and mentions it. Here, you could gain by talking about your church.
Third, if you don’t want your privacy invaded, you can diplomatically answer the concern behind the question without answering the question itself.
Example: If you are over 50 and are asked, “How old are you?” you can answer with a friendly, smiling question of your own on whether there’s a concern that your age my affect your performance. Follow this up by reassuring the interviewer that there’s nothing in this job you can’t do and, in fact, your age and experience are the most important advantages you offer the employer for the following reasons…
Another example: If asked, “Do you plan to have children?” you could answer, “I am wholeheartedly dedicated to my career“, perhaps adding, “I have no plans regarding children.” (You needn’t fear you’ve pledged eternal childlessness. You have every right to change your plans later. Get the job first and then enjoy all your options.)
Most importantly, remember that illegal questions arise from fear that you won’t perform well. The best answer of all is to get the job and perform brilliantly. All concerns and fears will then varnish, replaced by respect and appreciation for your work.