Référence bibliographique 
Journal of Youth and Adolescence, vol. 46, no 5, p. 995-1008.
«This study had two objectives: to identify and describe sexual trajectories from ages 16-22 based on the annual number of sexual partners, and to examine whether individual and family predictors assessed at ages 13-15 predicted trajectory membership.» (p. 1002)
Concerning first goal, «we expected to find at least three distinct trajectory groups. The first was expected to be characterized by sexual abstention, the second by at least one partner, and the third by having several partners, and always having the most relative to the other groups. [Concerning second goal, we] expected adolescents in the most extreme group to be more likely to have begun puberty earlier, be male, report higher levels of antisocial behavior, substance use and internalizing symptoms, have lower grades, not be living with both biological parents, and report lower parental monitoring than all the others groups.» (p. 998)
«This longitudinal study began in 2001 with 390 Grade 6 students [...] enrolled in eight elementary schools in a large French-speaking school district in Canada [Québec]. Of the 390 youth initially recruited, 78 % were still participating at age 22 (N = 303). In order to be included in the trajectory analyses, participants had to have at least 3 data points out of 7 between the ages of 16 and 22.» (p. 998)
Type de traitement des données :
«Adolescents do not all experience sexual development in the same way. For some, early sexual behavior is associated with potential risks and subsequent health outcomes, such as greater chances of sexually transmitted infections and more condomless sex […]. For others, early sexual experiences may act as stepping stones to a healthy adult sexuality and can therefore be seen as normative […]. Four distinct trajectories were identified. These trajectories differed with regard to the number of partners reported at age 16 (baseline), as well as the rate of change over time (slope). In short, individual factors (gender, pubertal timing, substance use and social competence) predicted group membership, whereas family factors did not.» (p. 1002) «In summary, the two groups at both ends of the continuum in our study (e.g., abstainers and multiple-partners) were more polarized than [in] Lansford’s [study.] One possible explanation for this divergence between the two studies may be cultural. In Quebec, women have their first child later than in the United States, at a mean age of 28.7 as compared to 26 […]. Quebec youth also tend to wait longer before getting married […]. Compared to American youth, fewer Quebec youth appear to follow the traditional model of marriage during emerging adulthood. As such, premarital sex is considered normative […].» (p. 1004)