Just had a mock interview today and was asked what was, in effect, a similar question, namely, can you give an example of a law not based on morality. I used the example of abortion law, stating that the law was passed by parliament in order to stop back-street abortions and not because of any moral belief that abortions were acceptable, and that, although they laid safeguards to prevent horrendous misuse, it still remained to the citizen to decide for themselves if abortion was right..... hope that helps??