Intermarriage or illicit cohabitation forbidden between blacks and whites. The first policy is to encourage childbearing among younger couples that involves marriage and cohabitation. Social monogamy refers to the cohabitation of one male and one female. Cohabitants can also regulate their relationship through a cohabitation agreement. This has led to a tendency toward later marriages and a rise in unmarried cohabitation. Studies have found that religious affiliation correlates with cohabitation and marriage entry. The church disagrees with extra-marital cohabitation. Today sixty percent of all marriages are preceded by a period of cohabitation. Over the past three decades rates of divorce, single parenting, and cohabitation have risen precipitously. Conflicting studies on the effect of cohabitation on subsequent marriage have been published. However, "de facto" polygamy or multiple cohabitation in and of itself is not a crime. This led to increased intermarriage and cohabitation with local white females. Religion can also lead to societal pressures against cohabitation especially within highly religious communities. Storgic love often develops gradually out of friendship, or out of extended duration of cohabitation. In the US cohabitation is generally associated with lower fertility.