Children live on in their mothers’ brains for decades, and not just as memories. Scientists have found pockets of male DNA, presumably from boy fetuses, in the brain tissue of women who died in their 70s.
Complete medical records, including pregnancy history, weren’t available for the women in the study, which means the researchers couldn’t rule out sources of cellular mingling other than male fetuses. The male DNA could have come from a male twin whose cells ended up moving into his sister’s body during pregnancy, for instance, or they may have come from an organ donation or blood transfusion, or even an older brother who had previously occupied the same uterus as the women.
What’s more, cells from several generations could mingle in a single person. Because cells also flow from mother to fetus, a pregnant woman possesses cells from both her mother and her child, and that child could inherit his grandmother’s cells.