The U.S. National Longitudinal Lesbian Family Study (NLLFS) is a large prospective cohort study of lesbian families and their children conceived through donor insemination (www.nllfs.org). Between 1986 and 1992, 154 lesbian mothers volunteered for the study with data collected through interviews and questionnaires. Additional data were obtained from offspring at ages 10 and 17 years through interviews. questionnaires and Child Behavior Checklists completed by the mother.