I was thinking about this mostly from the point of view of childcare burden disproportionately falling on women...
If you marry and older man, then the chances are higher that you will be the lower earner when the childcare decision gets made.
About 75-85 % of long term relationships have a younger female partner...so this might account for the bulk of gender bias in primary carer.
So is this an issue worth thinking about, and what might be done to make older female relationships more normal?