Under Section 16.1 of the Penal Law, bigamy and polygamy are illegal unless a legal defence is provided. Such defences include a defendant’s belief that his or her former spouse is dead. Under Section 16.3, abortion beyond the twenty-fourth week of pregnancy is illegal. An abortion is legal if it occurs only after a licenced physician determines there is a substantial risk that continuing the pregnancy would gravely impair the mother’s physical and/or mental health. An abortion may also be justified if the child would be born with grave physical or mental defects or if the pregnancy was the result of illegal intercourse such as rape. Additionally, the abortion must be sanctioned by two physicians who have certified in writing the reasons why the abortion is necessary. The Penal Law also prohibits a woman from carrying out an abortion herself by any means once beyond the twenty-fourth week of pregnancy.