On 13 May 2012, The New York Times published an article on childless women who are coming to egg freezing clinics with their parents (Gootman, 2012). The “would-be grandparents” are willing to pay the egg freezing costs for their daughters in the hope that their daughters, who have postponed their childbearing, are someday willing to start a family. One can consider that paying their daughters’ egg freezing provides an extreme case of how older parents can support the childbearing of their adult children. A more typical way is that older parents provide practical, emotional or financial support that may influence adult children’s fertility decisions. Whether kin support may influence fertility decisions of adult children is a topic that has received considerable attention, especially among evolutionary scholars. In this chapter we concentrate on the parental childbearing because fertility is an extremely important topic from the inclusive fitness perspective.