The multiple influences of maturation on adolescent male sexual behavior have been minimally studied. Interventions for the reduction of unwanted teen pregnancies and sexually transmitted diseases, including AIDS will be inefficient until the relationship of maturation the sexual practices of adolescent males is determined. The primary purpose of this proposed study is to test a theoretical model relating physiological, psychological, and cognitive maturity with sociocultural and demographic control variables to age of first coitus, condom use, and making a sexual partner pregnant. A cross sectional sample of 392 Hispanic males randomly drawn from an inner city high school (80%Hispanic) will allow the identification of age at first coitus, occurrences of safer sex practices and making a sexual partner pregnant. Data from in-depth interviews and written instruments will be used in multiple regression tests of the model. The results will expand the body of knowledge related to the sexual practices of Hispanic adolescent males. The study also allows for describing differences in sexual attitudes and behaviors among Mexican American and Puerto Rican males by country of origin and recency of migration. In addition, the data from males will be compared with similar data from pregnant and nonpregnant Hispanic adolescent females at the same school. The proposed methodology will enhance early identification of teens who practice risky sexual behaviors and facilitate self referral for health care. The results of this study will enable nurses, educators, and other professionals to identify those adolescents most at risk for early coitus and engaging in unsafe sexual practices. This, in turn, will allow for more precise prediction of male adolescents making a sexual partner pregnant and contracting STDs, including AIDS. Resources can then be directed toward extending age at first coitus and preventing pregnancies and STDs among those at highest risk.