Until the early 1900s, fathers were given custody of the children in case of divorce. Many U.S. states then shifted from this standard to one that completely favored the mother as the primary caregiver. In the 1970s, the Tender Years Doctrine was replaced by the best interests of the child as determined by family courts. Because many family courts continued to give great weight to the traditional role of the mother as the primary caregiver, application of this standard in custody historically tended to favor the mother of the children.