Co-parenting is an enterprise undertaken by parents who together take on the socialization, care, and upbringing of children for whom they share equal responsibility. The co-parent relationship differs from an intimate relationship between adults in that it focuses solely on the child. The equivalent term in evolutionary biology is bi-parental care, where parental investment is provided by both the mother and father. The original meaning of co-parenting was mostly related to nuclear families. However, since the United Nations Convention on the Rights of the Child, 20 November 1989, the principle that a child has to continue to maintain a strong relationship with both parents, even if separated, has become a more recognized right. Thus, the concept of co-parenting was extended to divorced and separated parents and to parents who have never lived together as well. Married and cohabitation parents Children benefit from more co-parenting, but the amount of co-parenting varies between couples. Bryndl Hohmann-Marriott has found that the level of collaborative co-parenting was higher among unmarried cohabitation parents and among those who married in response to pregnancy, compared to married couples that became pregnant during a marriage. In a shared earning/shared parenting marriage, child care is divided equally or approximately equally between the two parents. In a parenting marriage, the parents live and raise their children together in a purpose-based marriage without physical intimacy or expectation to share mutual romantic love. Separated parents Post-separation co-parenting describes a situation where two parents work together to raise a child after they are divorced, separated, or never having lived together. Advocates for co-parenting oppose the habit to grant custody of a child exclusively to a single parent and promote shared parenting as a protection of the right of children to continue to receive care and love from all parents. Epidemiological studies have shown that joint custody and other arrangements where children have greater access to both parents lead to better physical, mental and health outcomes for children. Elective co-parenting Elective co-parenting, also referred to as parenting partnerships or partnered parenting, may be used as a choice by individuals seeking to have children but who do not wish to enter into a conventional relationship. This phenomenon has been a common practice for gay men and lesbian women in the past, the concept has become recently more common among heterosexual men and women. Co-parenting by more than two adults Subject to the laws of their