Teenage subjects were recruited from five formal and informal Arizona educational programs, including some programs for pregnant teenagers. Pregnant teenagers were recruited upon admission to the programs to avoid contaminating the results with knowledge gained from their special curricula. Ninety never-pregnant teenagers and 50 teenagers pregnant for the first time were recruited in this manner. Additionally, 31 mothers who began childbearing after age 20 were recruited through health clinics and child care centers serving some of the neighborhoods from which the teenagers were recruited. Results indicate that the knowledge and attitude base of pregnant teenagers is almost identical to that of never-pregnant teens; however, adult mothers scored slightly but significantly higher than the teenagers on a measure of child-development knowledge and considerably lower than the teenagers on a measure of knowledge of sexuality. The results illustrate the importance of using comparison groups in studies of pregnant teenagers. The implications for sex education programs are discussed. 3 tables, 36 references. (Author abstract modified)