Recently one of my friend went to a local software company for an interview with HR and there he was asked some questions about his relationship status and some other personal questions.
So my question is what should be the reaction in this case ?
And should the interviewee oppose such questions ?

As an extension to the question this question may include some other questions which a normal person does'nt want to answer in an interview or does'nt feel comfortable answering ?

Recently, my friend attended an interview with a local software company. He was asked about his relationship status and some other personal questions. He wasn't comfortable answering such questions.

Is it right to ask such questions in the interview? How should the candidate handle such situations, where he is asked questions that are personal in nature or those he doesn't want to answer?