I just watched Man on Fire, a 1957 Bing Crosby movie about a nasty child custody dispute. (It is unrelated to the 2004 Denzel Washington thriller.)
The dispute was actually rather tame by today's standards. There were no accusations of domestic violence, alcoholism, drug abuse, or child neglect.
Crosby's wife ran off with a higher status man, and relinquished custody of their 8-year-old boy because she wanted to start a new family. But she has a miscarriage with the new husband and cannot have more kids, and sues for full custody. The boy, now 10, is strongly attached to the father and doesn't want to live with the mother.
Nevertheless, the female judge awards custody to the mother, and lets her move away to another city! The judge was portrayed as conscientious, but also arbitrary, capricious, biased, and cruel.
On one week's notice, the judge had briefs from both sides, and an investigator's report. It appeared that the parents were not allowed to see the report. The judge interviewed the boy with no one else present. The mother lies to the judge about why she waited two years to file for custody.
In the end, both parents are overcomed with noble thoughts, and offer each other full custody. Everyone agrees that the lesson from King Solomon was that a parent can prove greater love for the child by being more willing to give up the child. The father has the greater love, lets the boy go with the mother, and the father gets a new girlfriend. I guess that this is what the 1950s movie audience expected.