It is a too general question and there is no hard and fast rule.
It also depend on organisation to organisation and geographical location of the organisation. for instances, in USA you cannot ask marital status or maternity status.
Well, if your organisation believe that the family background of the candidate matters, you may ask question related to it. However, it depends. If an organisation has something to hide, it will not hire a candidate who has political, police or law enforcement link. For safer side also few organisation may avoid such candidate.
You may ask about the goal of the candidate, what has he/she planned for his/her career. You may check whether he has studied the job description well and has done study of the company it business etc. (I do not prefer a candidate who has not done this basic study)
HR should also have basic knowledge of the function and technicality and cross check whether the candidate possess required knowledge. for instances, if you are hiring an entry/junior level accounts payable person whether he knows rate of TDS deduction and threshold limit.
The question related to reason for changing job, background of the company are also important. Apart from this, there are several other question which you need to think logically and apply scientifically.
30th December 2013 From India, Mumbai