In feminist circles, there is a common understanding that the reason fathers are less likely to get custody due to the patriarchal belief that men can't be good parents. Whether you agree or disagree with the patriarchy theory is up to you, but this notion needs to go. In an actual patriarchy, men would be getting custody all the time. That's how it was before the "tender years doctrine", which "presumes that during a child's "tender" years, the mother should have custody of the child. The doctrine often arises in divorce proceedings." This was made by a feminist, Caroline Norton, to combat the patriarchy, and as a result it flipped the whole dynamic to make it so that only women were to get custody. So the notion that the patriarchy is why men get discriminated in custody cases, even if you agree with the patriarchy theory, needs to go.