Lyons, Heidi A.Manning, Wendy D.Longmore, Monica A.Giordano, Peggy C.2014-12-032014-12-032014Lyons, Heidi A., Wendy D. Manning, Monica A. Longmore, and Peggy C. Giordano. Forthcoming. “Gender and Casual Sexual Activity from Adolescence to Emerging Adulthood: Social and Life Course Correlates.” Journal of Sex Research.http://hdl.handle.net/10323/3207The prevalence of casual sexual activity among teens and emerging adults has led to much public attention. Yet limited research has investigated whether the number of casual sexual partners per year changes as heterosexual men and women transition from adolescence into emerging adulthood. We considered the influence of social context and life course factors on the number of casual sex partners. We examined four waves of interviews from the Toledo Adolescent Relationships Study and used negative binomial growth curve models to investigate patterns of change in the number of casual sex partners (N = 1,196) ages 15 to 22. Men and women both reported increases in the number of casual sex partners over time, and did not differ from each other in the rate of change over time. Forty percent of respondents reported a recent casual sex partner at age 22. Number of prior dating relationships, education status, substance use, and perceptions of peer sexual behavior significantly influenced the number of casual sex partners. Emerging adults who did not complete high school, compared to those enrolled in four-year degree programs, reported significantly more partners. The findings contribute to research on intimate relationships and provide insights for programs targeting emerging adults.en-USCasual sexYoung adultsLife courseArticle