Does any research into the differences between male and female distinguish between females who have experienced pregnancy and childbirth and those who have not? It’s doubtful, since most research is conducted by men, to whom making such a distinction would not even occur.
But there are permanent changes to the brain as a result of pregnancy and childbirth. “Gray matter becomes more concentrated” and “Activity increases in regions that control empathy, anxiety, and social interaction.” There are also changes in the amygdala, “which helps process memory and drives emotional reactions like fear, anxiety, and aggression” (https://www.theatlantic.com/health/archive/2015/01/what-happens-to-a-womans-brain-when-she-becomes-a-mother/384179/)
So are the much touted differences between male and female differences between male and only mothering females? If so, that entire area of research needs to be redone.
