The first study assessed sexual attitudes and behavior of 850 adolescents. In this group, 89 percent of the males and 39 percent of the females said they had experienced coitus. Youngsters of upper middle and lower middle socioeconomic status had higher rates of coital activity than did those of the middle class. Only 10 percent of the sexually active couples were using some type of contraception. Boys indicated greater inclination toward "recreational" sex, while girls tended to be more effectively involved with their lovers. Ninety-six percent of sexually active girls planned to marry their current partner, while 5.5 percent of the boys planned to do so. The second study assessed the prevalence of pregnancy in minors (17 years or younger) attending the gynecology department at a local general hospital. Over a period of two years, 551 cases were identified. Although rates of pregnancy increase with age, the rate of annual increase was dramatically highest from ages 13 to 14, after which it decreased progressively with age. Based on these results, it is recommended that, at least in the Guatemalan population, sex education be implemented at an early age in order to prevent adolescent pregnancy. 4 tables, 1 figure and 24 references. (Publisher abstract)