Someone who shares in the parenting of a child or children, such as
A godparent.
A divorced or separated parent who shares custody with the other parent.
A parent in a same-sex couple.
To act as a co-parent; to share custody of a child or children; to share in the responsibility of parenting a child or children.
A woman who gives birth to a child not her own, with the intent to give that child up to at least one of the biological parents once it is born.