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" refers to studies based in African hunter-gatherer groups showing that grandmothers are sexier than mothers.
( z1 refer :ARG1 ( z2 thing :ARG1-of ( z3 hypothesize ) :mod ( z4 person :ARG0-of ( z5 have-rel-role :ARG2 ( z6 grandmother ) ) ) ) :ARG2 ( z7 study :ARG1-of ( z8 base :location ( z9 group :ARG0-of ( z10 hunt ) :mod ( z11 continent :name ( z12 name :op "Africa" ) ) ) ) :ARG0-of ( z13 show :ARG1 ( z14 have-degree :ARG1 z4 :ARG2 ( z15 sexier ) :ARG3 ( z16 more ) :ARG4 ( z17 person :ARG0-of ( z18 have-rel-role :ARG2 ( z19 mother ) ) ) ) ) ) )