[...] visitation rights are considered to arise from the very fact of parenthood, so that parents are entitled to this right simply by being legally recognized as parents. [...] visitation rights are subject to the general rule of parental exclusivity: only a child's legal parents have rights considered parental, and non-parents cannot acquire them.
Rethinking Visitation: From a Parental to a Relational Right,
16 Duke Journal of Gender Law & Policy
Available at: http://scholarship.law.duke.edu/djglp/vol16/iss1/1