Previously existing ideas on how advanced maternal age affects adult health of children have to be reconsidered. It had been thought that mothers delivering later in life have children that are less healthy as adults, because the body of the mother had already degenerated due to physiological effects like decreasing oocyte quality or a weakened placenta. In fact, what affects the health of the grown-up children is not the age of their mother but her education and the number of years she survives after giving birth and thus spends with her offspring. This is the conclusion of a new study by Mikko Myrskylä from the Max Planck Institute for Demographic Research in Rostock, Germany carried out with data from 18,000 US children and their mothers.