>>21635228It doesn't just fit perfectly for the age gap, it also fits perfectly for a perpetual cycle of breeding to support population growth without incest in an evolutionary context:
M=male, F=female, C=children (think average age, F20 can mean conception at age 19,20,21 for 3 children)
gen1: M30,F20,C0: male dies, children are born
gen2: F30, C10 (puberty): boys learn to hunt and fight and girls learn to take care of children, female took care of children and dies
gen3: C20: Females get bred by successful males (30), younger males (20) hunt and fight in their prime, few will survive until late 20s but those who do gain breeding rights
And thus the strong successful males get to breed multiple females, while the unsuccessful careless females kill an entire generation of children
Strong male genes are passed on, caring female genes are passed on.
