It isn't a bad thing nobody said it was. But biologically speaking women are more wired to deal with infants and toddlers than men and there obviously evolutionary reasons to this shit. It's neither good nor bad.
We don't live in a caveman society, children need both parents and any reason why they would only need a mother evolutionarily will just be inevitably anachronistic
We don't live in caveman era but we haven't changed from 90 000 years ago our biology is congruent to what it was 90k years ago. Yes we are more educated but we still are driven by purely genes