In a recent interview, I was asked some questions about my marital status and family life. I realize that this is inappropriate as well as illegal. I got around the questions but want to get some advise on this in the future

Unfortunately, there are interviewers who do not know which questions are improper to ask. Here are a basic set of rules to go by when interviewing and how to handle them.
Illegal questions are those that the interviewer has not right to ask, these types of questions are related to age. Gender, race, religion and sexual orientation. Inappropriate questions are those that may relate to circumstances that are not specific to the job in which you are interviewing.
The good news is that there are ways to avoid this without disrupting the interview. If you are really interested in the position, it would be best not to embarrass the interviewer but you can simple redirect the statement by asking ?Does my marital status have anything to do with the job?? or ?Do you think that a single/married person could perform this job better?? or ? The job qualifications did not state that you were looking for someone single/married?. However, if the questions are offensive and you would not consider working there - get out. Simply say, ?The questions that you are asking are not relevant to the job. I don’t think that the intimate details of my personal life have any bearing on the fact that I can do this job. While I appreciate you trying to establish a relationship, I think that it would be better to end this interview.? The End!