As cohabitation has risen dramatically in the past few decades among adults of all ages, it is possible that middle-and older-aged parents are “learning” cohabitation from their young adult children. The present study uses this theory as a guiding framework to determine if parents are more likely to cohabit themselves following the start of a young adult child’s cohabitation. Using three waves of the National Survey of Families and Households (N = 275), results show that union formation patterns are influenced by young adult children among parents who are single at their child’s 18th birthday. Parents are less likely to marry than remain single and are much more likely to cohabit than marry if they have a young adult child who cohabits. These results show support for the hypotheses.