The following marriages are illegal in South Dakota:
1. Any marriage between parents and children, ancestors and descendants of every degree, and be- tween brothers and sisters of the half as well as the whole blood, and between uncles and nieces, or aunts and nephews, and between cousins of the half as well as of the whole blood (otherwise known as incestuous marriage) is null and void from the beginning.
2. Any marriage of a stepfather with a stepdaughter or a stepmother with a stepson is null and void from the beginning.
3. Any marriage contracted by any person during the life of a former husband or wife of such person with any person other than such former husband or wife (otherwise known as a bigamous marriage), is null and void from the beginning.
4. Any marriage is voidable if one person is physically incapable of entering into the marriage or the consent was obtained by fraud or force.