Earlier quoted context omitted.
After pregancy and the very first months of life, I fail to see any "obvious biological reasons".
WHO recommends breast feeding until age of 2, so that's at least one thing that seems not readily changeable across sexes.
https://www.who.int/topics/breastfeeding/en/
>Exclusive breastfeeding is recommended up to 6 months of age, with continued breastfeeding along with appropriate complementary foods up to two years of age or beyond.