Parents often complain that grandparents meddle in child-rearing. New research suggests that such meddling starts in the womb, where cells from grandma manipulate the mother’s immune system.
Scientists already knew that during pregnancy some cells from the fetus invade the mother, while cells from mom sneak into the offspring. These interloping cells can survive for decades (SN: 11/3/12, p. 12). Some research suggests that fetal cells help mom repair damaged tissues or, on a darker note, promote autoimmune disease (SN Online: 5/10/15). But it’s not clear what a mother’s cells do in her offspring.