Grandmother Hypothesis

Did you ever wonder why we women folk live past our useful (fertile) years?  Why we just don’t die off when our last viable egg goes towards the light?  Our primate cousins don’t make it to menopause:

“For example, among our closest living relatives, chimpanzees, female fertility declines at about the same age as in people, from a peak before age 30 to virtually zero at age 45 (ref. 3). But chimpanzee survival rates fall along with fertility, so that in the wild less than 3% of the adults are over 45.” – More from

Turns out, in evolutionary speak, we need grandmothers.  While the men continue to hunt, these women gather to feed their daughter’s older children while she is nursing her newborn (and is therefore vulnerable outside the cave).  This basic nurturing allows our offspring to keep making babies and thus satisfying our evolutionary needs.

But it gets better:  Grandma may actually like you more.

The grandmother hypothesis is based on the fact that women are genetically related to their grandchildren, and we should not overlook the nature of that genetic relatedness.

Paternal grandmother–girl: 50 per cent
Paternal grandmother–boy: 0 per cent
Maternal grandmother–boy and maternal grandmother–girl: 25 per cent

“The higher the X-relatedness between a grandmother and grandchild, the more beneficial effect the grandmother has on that child’s survivorship.”  So, science says, if you are your father’s daughter then his mother loves you more than your brother.

The holidays are coming Dear Readers.  Use this information in whatever way you deem fit.

And a big whoop-de-whoop for all grandmothers out there.  You keep on keepin’ on.


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