This report finds that the share of young adults (ages 25–34) living with their parents increased from 12 to 22 percent between 2000 and 2017, adding 5.6 million more young adults living in parent’s home. The researchers examine the causes and consequences of this change and conclude that this could have a long-term negative impact because young adults who live at home longer are less likely to move out in the future. At the same time, these extended stays are not better positioning young adults to access homeownership, a critical source of future wealth building.