This topic has obviously become highly socio-political. The current fashion is that there are basically NO biological sex-type differences; that any sex-type differences are socially imposed and generally disadvantageous to women. I think a meta-study style article like this useful to show all the rich and varied science on the matter and to help spark a dialogue around "what if?". If we assume even half of the impli…
In pair bonding species, sex-type differences are few. In the extreme end, some species can even switch gender depending on the local balance. Some fish even "keep track" of who went female/male last time, as eggs cost more energy to produce. Those that cheat are then shunned.