Yeah. One idea is that, since our offspring take SO long to mature and take so many resources relative to other animals, that it makes more sense at some point for mothers to devote their resources to existing children rather than focus on trying to have more. So it benefits us as a species to have "support" people like grandmas in our society. This is getting into a tangent but there are all sorts of things that kinda "make sense" if you think about life before modern society. Homosexual men would have probably been an evolutionary advantage to a clan of early humans since it would have provided extra strong male bodies without adding to mating pressure. People with a preference for staying up at night and sleeping during the day could have provided more alert guards to watch for predators. Etc etc.