ABSTRACT
The impact of biological maturation on alcohol habits, as determined by the prevalence of drunkenness at the three ages in mid-adolescence, seem to be temporary and restricted to a relatively short period. For sexual intercourse the differences among the several menarcheal groups of girls widened over the time period in midadolescence. Education about sexuality, about living together, about contraceptive use, and so on, is obligatory in the elementary school. The same tendency with the early-matured girls being more advanced in their contacts with boys could also be observed for frequent sexual intercourse at both test occasions. The same was true for the observation that the increase over time for frequent sexual experiences was greater for the early-matured girls than for the later-matured. The behavior differences among the four menarcheal groups of girls at 14.5 years, whether sexual intercourse, running away from home, use of hashish, drunkenness, or psychosomatic reactions were considered, were also profound at 15.10 years of age.
