Sex with an underage wife is rape, the Indian Supreme Court said on Wednesday, reports NDTV.Exempting married women between 15 and 18 from this rule is unconstitutional, the court also said."If a man has sexual intercourse with a wife who is below 18 years, it is an offence. The minor wife can complain against the husband within one year," said the court.Under the Indian Penal Code or IPC, a man having sex with a girl below 18 - with or without her consent - is defined as a crime. However, an exception is made if the girl is his wife and not below 15.The court today ruled that the exception is illegal.The petitioner in this case, Independent Thought, had argued that there is a conflict in the law for sex with underage girls and with girls who are married.The Protection of Children from Sexual Offences Act (POCSO) terms children as those who are below 18 years old. The petitioner pointed out that the criminal law said a man is not guilty if he has sexual intercourse with a child, if she is more than 15. This, when child marriage is illegal.