Examined the validity of adolescents' reports of their mother's age. Most research on the validity of self-report focuses on personal behaviors such as alcohol and substance use, or response bias due to social desirability. Few studies investigate the validity of adolescents reporting of nonsensitive information. Data from 80 mother-adolescent pairs were collected. The sample included 9th graders from four high school English classes, equal numbers of males and females, and 15% African Americans. The correlation between mothers' reports and youths' reports of mother's age was .99, and 95% of the youth were within a year of their mother's correct age. No race or gender differences were found. These results allow researchers to examine adolescent outcomes for youth born to teen mothers without the expense of also collecting data from their mothers. Results also suggest that adolescents' self-reports of other nonsensitive familial data may also be valid.