 20th-century international human rights documents explicitly codify the right “to marry and found a family” (United Nations 1948, Article 16), and thus some writers argue that liberal constitutions implicitly enshrine a right to procreate (Hill 1991). A right to procreate could be construed negatively or positively. As a negative right, it would be a right against coercive interference in decisions regarding procreation. As a positive right, it would be an entitlement to assistance in procreation.