The breathtaking acceleration of the average life expectancy is a global issue. In particular, the very old represent the fastest growing population group in industrialized countries worldwide. This trend in population aging gives rise to a new phenomenon: family members reach (old and) very old age together. Specifically, about two thirds of the very old have children who have reached old age themselves. Since most very old persons have outlived spouses and friends, children are likely to become their primary social contact. Yet there is virtually no research on this specific relationship constellation, very old parent with advanced-age child. Given the importance of close social relationships for well-being and health, with protective effects of high-quality and the potential harm of low-quality relationships, investigation of the very old parent-child constellation is imperative. Besides addressing the effects that the involvement of their children has for the life of the very old parent, it is also important to consider that many advanced age children have health issues and may feel particularly burdened due to compromised goals and prolonged caregiving. Furthermore, as research documents physical and mental health difficulties associated caregiving including enhanced mortality risk, the children of the very old may be at risk. Together with Prof. Kathrin Boerner (University of Massachusetts, Boston), we have examined the relationship between very old individuals and advanced age children in the context of the Second Heidelberg Centenarian Study and the Fordham Centenarian Study. More recently, we have started investigating this phenomenon also in Switzerland, with the support of Fondation Leenaards (Quality of Life in Older Adults Award 2015, in the category Exploratory Study; together with Profs. Joelle Darwiche and Dario Spini [University of Lausanne] and Prof. Heining Cham [Fordham University, New York]). Since September 2016, we have been able to extend this study with the support of National Research Center of Excellence LIVES (2016-2018). In September 2017, we started a new study on this topic in the USA funded by the US National Institute on Aging, which will be conducted at University of Massachusetts, Boston under the lead of Prof. Kathrin Boerner.