The so-called "grandmother hypothesis", based on studies of African hunter-gatherer groups, suggests that infertile women are vital for successful child-rearing despite being unable to produce children themselves.
The "grandmother hypothesis" is based on Asian cultures
( z1 base :ARG1 ( z2 hypothesize :ARG1 ( z3 person :ARG0-of ( z4 have-rel-role :ARG2 ( z5 grandmother ) ) ) ) :ARG2 ( z6 culture :mod ( z7 continent :name ( z8 name :op "Asia" ) ) ) )