With all due respect to mother's and fathers. I think the tender years doctrine (despite the PC BS that demands courts rule to the contrary) is still important. The notion is that children need their mother in at least the first three (though I have heard five) years of their development.
A new developing child needs a mother in those tender years.
A new developing child needs a mother in those tender years.
And then kids need you even more when they are teens.
And a Father.