Definition of good and bad stands on the morality and character. It applies to both boys and girls. Those who loose their own moral values and harm their own self respect are considered bad. Society can’t judge the person better than himself/herself. Having sex with someone doesn’t make one bad. Those are considered bad who harm their own conscience for mere gratification.  Those who use others badly for their mere benefits are bad. Those who lost their self-respect, moral values and ethics are harmful to others and they are bad.