TOM JAMES: The Maternal Preference in 19th Century American Law.

What this meant was that, in practice, the courts of every state – those that had openly rejected the “fathers’ rights” doctrine from the beginning, and those that had given it lip service while effectively nullifying it through the application of broad exceptions – decided custody on the basis of the best interests of the child, with a strong presumption that maternal custody was in a child’s best interests.

The maternal preference was based on strongly held beliefs about the natural superiority of women and the inferiority of men, as a class, with respect to child-rearing functions.