Predictive relationship between adolescent oral and vaginal sex: results from a prospective, longitudinal study.
OBJECTIVE
To (1) identify the temporal order between oral and vaginal sex onset; (2) test whether oral sex or vaginal sex is a risk or protective factor for the other; and (3) determine whether the relationship between oral and vaginal sex varies across time.


METHODS
Prospective, longitudinal study with 6-month assessments conducted between 2002 and 2005.


METHODS
Self-administered surveys completed during class time.


METHODS
At baseline, 627 ninth grade high school students from 2 northern California schools were included in the study.


METHODS
Oral and vaginal sex onset.


RESULTS
Among sexually active adolescents, most initiated vaginal sex after or within the same 6-month period of oral sex initiation. Adolescents who initiated oral sex at the end of ninth grade had a 50% chance of initiating vaginal sex by the end of 11th grade. In comparison, adolescents who delayed until the end of 11th grade had a 16% chance of initiating vaginal sex by the end of 11th grade.


CONCLUSIONS
The first 2 years of high school may be a critical age period for adolescents' vulnerability to vaginal sex initiation via oral sex behaviors. Comprehensive evidenced-based interventions and provision of preventive services aimed toward reducing sexual risk should be expanded to include the role oral sex plays in adolescent sex behavior.
Division of Adolescent Medicine, Department of Pediatrics, University of California-San Francisco, 3333 California Street 245, San Francisco, CA 94118, USA. anna.song@ucmerced.edu
Anna V
AV
Song
Bonnie L
BL
Halpern-Felsher
D000293:Adolescent; D000294:Adolescent Behavior; D000367:Age Factors; D002140:California; D003075:Coitus; D005260:Female; D006801:Humans; D016015:Logistic Models; D008137:Longitudinal Studies; D008297:Male; D011446:Prospective Studies; D012309:Risk-Taking; D012725:Sexual Behavior / Q000706:statistics & numerical data*