In regard to social peer relationships, family characteristics may predict an adolescent's involvement and success in dating. A longitudinal study of 73 subjects from the Minnesota Parent-Child Longitudinal Project by Madsen, Patterson, and Hennighausen (2001) focused on this relationship. At age 16, a group of 164 subjects and their mothers were interviewed about the teen's involvement in dating; at age 20-21, 73 of the original participants and their romantic partner of four or more months were interviewed about their current relationship. The researchers concluded that "the mother's level of knowledge about the adolescents' dating experiences predicted quality romantic relationships five years later" (S. D. Madsen et al., 2001). This may be due to a greater opportunity for parent-child guidance in romantic relationships, or to a potentially protective influence parents may have against certain negative aspects of dating (Hansen et al., 1992).