As the old folks around here used to say, a mother can always claim her own, a father takes his by faith alone. Also, in prehistoric times, I’d make the wild guess that the men had more to say about mating that even the most rabid feminazi says prevails today.
Change in Ph has an impact on which (X or Y) wins that first race, so that probably had an impact. A relatively small skew over a pretty long period of time (and short onset of next generations) could easily put a lot of men into the local pool, and additional women had to be found.
“momma’s baby and daddy’s maybe”