Under Section 16.1 of the Penal Law, bigamy, and polygamy are illegal unless a legal defense is provided. Such defenses include a defendant’s belief that his or her former spouse is dead. Under Section 16.3, abortion beyond the 24th week of pregnancy is illegal. An abortion is legal if it occurs only after a licensed 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 24th week of pregnancy.