Background: Personal beliefs about sexual attitudes and rights likely affect reproductive health behaviors. We examined the prevalence and predictors of low sexual assertiveness (SA) among sexually active females across three age groups (14-17 yo, 18-21 yo, and 22-26 yo).Methods: 904 white, black, and Mexican-American females presenting at community-based family planning clinics in Southeast Texas between April 1997 and February 1998 completed an anonymous self-report questionnaire that assessed demographic and reproductive characteristics, dating behaviors, mental health measures and occurrence of physical and sexual assault. Subjects also completed a sexual assertiveness scale that assessed one's right to make various reproductive health decisions and sexual communications to partners. A total SA score was obtained by summing the 13 items; scores were then dichotomized so those scoring in the lowest quartile could be compared to the others. Data were analyzed using chi-square and logistic regression stratified by age group (244 aged 14-17; 392 aged 18-21; and 268 aged 22-26).Results: 27% of subjects aged 14-17, 22% aged 18-21, and 17% aged 22-26 were identified as having low SA. For 14-17 years olds, logistic regression analyses revealed that those with low SA as compared to adequate SA were significantly more likely to be Mexican American (OR = 4.8) or black (OR = 3.1) than white, to have hand </= 1 dating partner in the last 12 months (OR = 1.8), and to report inconsistent birth control in last 12 months (OR = 2.0). Among 18-21 years olds, low (SA) was related to reporting forced sexual contact in the last 12 months (OR = 5.2), moderate-to-severe depressive symptoms (OR = 3. 0), no history of physical abuse (OR = 2.5), believing that your partner is monogomous (OR = 2.6), married or living with a male partner (OR = 2.1), </= 3 lifetime sexual partners (OR = 1.8), not using alcohol before sex (OR = 1.8), and gravidity >/= 1 (OR = 1.8). Among 22-26 years olds, low SA was associated with gravidity >/= 1 (OR = 2.8), being a high school dropout (OR = 2.1), and inconsistent birth control use in the last 12 months (OR = 1.9).Conclusions: These data suggest that 1 in 4 sexually active women report low SA and for two age groups these attitudes are associated with inconsistent contraception. Among 18-21 years olds, low SA is also associated with forced sexual contact and depressive symptoms. Thus, efforts to prevent unintended pregnancy and unwanted sexual contact may be more effective if individual levels of SA are taken into account.