Sexual initiation and developmental changes.

Abstract

ADOLESCENCE IS A UNIQUE developmental stage in the life cycle of human sex and sexuality. During this stage, young people experience relatively rapid changes in cognitive, emotional, and physical capacities, and also in family and social relations (e.g., growing autonomy from parents, greater peer affiliation, and gender dynamics). All these domains have significant effects on sexual behaviors. As an implication that these rapid changes occur, we expect sexual behaviors and their determinants to differ by age. The factors that motivate a 14-year-old to engage in sexual intercourse and use condoms may not be the same as those for a 17-year-old. Fundamental data that focus specifically on developmental changes in sex and sexuality during adolescence are lacking. Without these data, interventions run the risk of developing a “one size fits all” approach, which because of its insensitivity to age differences may fail for adolescents as a whole, and may not be effective for any specific age group. One reason for the lack of data on developmental changes in sex and sexuality is that such data are difficult to collect. Aside from obvious political and ethical issues that these studies create, there are operational and analytic complexities in conducting the necessary studies. The report by Rosenthal and colleagues clearly struggled with these challenges and overcame many of them to emerge with some important insights into the age-related difference in adolescents’ reasons for engaging in sexual intercourse. Under ideal conditions, investigators conducting adolescent developmental studies would recruit and enroll early adolescents, then follow and assess them regularly until they are late adolescents or young adults. Such a longitudinal design allows for within-subject analysis of changes, which is the gold standard for tracking age-related changes. This design contrasts with cross-sectional data analyses, in which early adolescents are compared with middle or late adolescents on the basis of age, using a between-subject analysis. Between-subject analyses may be biased by cohort effects. Temporal shifts in sexual and contraceptive behaviors may confound the interpretation of age differences. For example, a school district may enact a sex education curriculum program at different grade levels, which could shift norms in these grades. Although prospective research is needed, it is difficult to retain adolescent participants, especially high-risk adolescents, over a period of time sufficient to observe hypothesized changes. Adolescents move in and out of study catchment areas, change addresses within catchments, and become lost to follow-up evaluation, or they may change their minds about participating in the study after one or more visits. These problems contribute to mounting attrition rates as the studies continue. Rosenthal and colleagues used an innovatively combined cross-sectional and longitudinal design. They were able to retain 75% of their sample through at least five of a possible seven study visits over 3 years, and thus could examine within-subject changes over time in adolescents’ reasons for having sex. Because initiation of sex is a one-time event, the investigators conducted a between-subjects cross-sectional analysis for this behavior, comparing younger and older adolescents. Assuming factors that vary by age are developmentally based, this study provides important insights into developmentally based reasons for initiating sex and engaging in sex thereafter. A review of the study results makes it apparent that the adolescents’ reasons for initiating sex were similar to the reasons for having sex once they had become sexually active. Peer-related sexual behavior was reported by younger girls as a reason for having intercourse, whereas relationship factors (i.e., physical or emotional attraction) were a reported reason among older girls. This makes sense in light of theoretical and empirical developmental data, which suggest that peers may be an important influence during early to middle adolescence, and that relationship factors are relatively more important during later adolescence. It was disturbing to see results suggesting that younger adolescents are being coerced into having intercourse. Of the girls who initiated sex when they were younger than 15 years old, 21% reported as a reason for initiating sex that their partner made them feel they had to have sex. Similarly, younger age was associated with adolescents’ reports that partners making them feel they had to have sex was a reason for having sex. These findings suggest that sexual coercion should be another focus of interventions targeting younger adolescents. This study provides powerful evidence of the need for adjusting interventions to account for the developmental differences described. Future studies are needed to explore factors that account for different developmental trajectories and investigate developmentally based reasons for using or not using condoms and contraceptives.