There is a theory that humans’ long life spans and women’s long postreproductive lives, might be connected through the grandmother effect. “…An analysis of church birth and death records in Finland for individuals born between 1731 and 1890 showed that having a maternal grandmother between 50 and 75 years of age while a grandchild was 5 years old or younger increased the child’s survival… The second study … it’s not just the existence of a grandmother, but her proximity that matters. The shorter the distance between grandmother and grandchild, the more involved the grandmother can be and the more benefits that accrue to her daughter and grandchildren…” See More.