Historically, grandmothers have been important to their grandchildren, and the help provided by grandmothers has increased grandchild survival during the times of high child mortality. However, there have been signs that in many populations, the impact of maternal grandmothers and paternal grandmothers on their grandchildren has been different. A recent study shows that X-chromosome relatedness between grandmothers and their grandchildren did not affect grandchild survival in the 18th and 19th century Finland.