<p><strong>STUDY OBJECTIVE: </strong>To describe sexual initiation pattern in female adolescents and examine its association with adolescent characteristics and racial disparities in adverse sexual health across adolescence into early adulthood.</p>

<p><strong>DESIGN: </strong>A prospective, longitudinal, observational study from adolescence to adulthood.</p>

<p><strong>SETTING: </strong>Nationally representative, the National Longitudinal Study of Adolescent to Adult Health data, ranged 24-32 years old at final assessment.</p>

<p><strong>PARTICIPANTS: </strong>43,577 US females in 1994-2008.</p>

<p><strong>INTERVENTIONS AND MAIN OUTCOME MEASURES: </strong>Adolescent sex related characteristics in individual-family-school peer level were accessed, and multiple sex partners, STIs/HIV, and inter-partner violence (IPV) were longitudinally tracked. The sexual initiation pattern and its longitudinal association with sexual health were analyzed using latent class analysis and Mixed-effects Poisson regression models.</p>

<p><strong>RESULTS: </strong>The sexual initiation patterns were determined as normative (65.9%), late (24.8%) and early but unempowered (9.3%). The highest rate of early-unempowered group was shown in Hispanics (14.4%); they were more likely to be depressed, unsatisfied with their bodies and on welfare and have less educated/permissive parents to their sexual initiation than others. The late group had a higher BMI and more satisfaction with their bodies. The highest number of STIs/HIV and IPV victimization was shown in non-Hispanic blacks (NHBs) and Hispanics, respectively. However, NHB females' higher STIs/HIV was shown in late/normative groups, not in early-unempowered group. Among Hispanic females, adolescent sexual initiation patterns were not directly associated with their frequent IPV victimization.</p>

<p><strong>CONCLUSIONS: </strong>NHB females' higher STI/HIV in late/normative groups and Hispanic females' frequent IPV victimization regardless of their sexual initiation patterns may indicate that racial/ethnic disparities in female sexual health was not directly determined by adolescent risk behaviors.</p>