On Paternal Grandmothers.

Despite the caveat at the end of this article, I've decided to post it.  In short: 

A little math shows that maternal grandmothers are related to granddaughters and grandsons equally, for an "X-relatedness" of 25 percent. But paternal grandmothers are twice as close to granddaughters (50 percent) and not at all to grandsons (zero percent).