23 Pa.C.S. § 5327: Presumption in cases concerning primary physical custody.

(a) Between parents.--In any action regarding the custody of the child between the parents of the child, there shall be no presumption that custody should be awarded to a particular parent.

(b) Between a parent and third party.--In any action regarding the custody of the child between a parent of the child and a nonparent, there shall be a presumption that custody shall be awarded to the parent. The presumption in favor of the parent may be rebutted by clear and convincing evidence.

(c) Between third parties.--In any action regarding the custody of the child between a nonparent and another nonparent, there shall be no presumption that custody should be awarded to a particular party.