alt Hacker News100% agree with this. But its not uniform for everybody, mothers generally change and throw away previous life after having kids in ways that most men don't. Some fathers are similar (and few mothers are similar to average guy) but difference is pretty big when you dig deeper.
That's mostly due to social pressures and expectations - women are expected/demanded/forced to perform most of the child care duties. Which is why when a man does child care (in the US at least), he is seen as "helping out", even if he is the full-time caretaker/househusband.