Prevalence of adolescent experience of oral-genital, vaginal, and anal sex
displays sociodemographic characteristics of our analytic sample, the prevalence of experiencing oral-genital, vaginal, or anal sex during adolescence (i.e., by age 18) for the total sample and by sociodemographic groups, and adjusted odds ratios for associations between each sociodemographic characteristic and behavior. Overall, about two-thirds of adolescents experienced oral-genital sex and three-quarters experienced vaginal sex. Anal sex was the least common, at about 11%.
Sociodemographic characteristics of the analytic sample, prevalence of oral-genital, vaginal, and anal sex by age 18 by sociodemographic characteristics, and adjusted odds ratios (aOR)a (n=13,835)
Higher percentages of females than males experienced vaginal sex during adolescence, but males were more likely to experience oral-genital and anal sex (). About three-quarters of non-Hispanic (NH) whites and NH American Indians had oral-genital sex by age 18; among other race/ethnic groups, percentages ranged from 50 to 68%. Prevalence of vaginal sex experience also varied by race/ethnicity, although NH Asians were the only group with significantly lower odds of experiencing vaginal sex compared to NH whites. With the exception of NH whites and American Indians, vaginal sex was more prevalent than oral-genital sex during adolescence. This difference was especially striking for NH blacks, with 81% reporting vaginal sex but only 50% reporting oral-genital sex. Differences between NH black and NH white males and females were similar in magnitude and direction for vaginal and anal sex, but strikingly different for oral-genital sex. Three quarters of white and 79% of black males reported adolescent oral-genital sex experience. However, among females, 70% of whites but only 38% of blacks report oral-genital experience (results not shown). Overall, NH blacks were also the least likely to report adolescent anal sex (6%), and were the only group whose odds of experiencing anal sex were significantly lower than NH Whites.
Respondents from family structures other than two biological parents were more likely to report oral-genital and vaginal sex, with higher percentages reporting vaginal than oral-genital sex. In contrast, similar percentages of respondents from households with two biological parents reported oral-genital and vaginal sex during adolescence. Percentages reporting anal sex were similar across family structure groups (10% to 12%), with the exception of the single father family structure (18%).
Respondents with college-graduate parents were least likely to report vaginal sexual experiences, but unlike other groups, similar percentages reported oral-genital and vaginal experience (about 67% for each behavior). Higher percentages of respondents with less educated parents reported anal sex. Compared to respondents with typical pubertal timing, earlier maturing adolescents had greater odds of reporting each type of experience. Later-maturing respondents had lower odds of oral-genital experience. Older respondents were more likely to report adolescent oral-genital and vaginal sex.
Typicality of earliest behavior
shows the percentages who initiated each of the three sexual behaviors first, as well as percentages reporting no oral-genital, vaginal, or anal sex by age 18. The last column indicates percentages who reported the same age at initiation for two or three behaviors. Overall, similar percentages (33%) either had vaginal sex first or initiated two (typically oral-genital and vaginal) or three behaviors at the same age (i.e., within a 12 month period) versus initiating oral-genital sex first (15%). Less than one percent reported anal sex as their first behavior. About one in five respondents reported no experience as of age 18.
Weighted percentages of respondents who report, by age 18, no sexual activity, oral-genital sex first, vaginal sex first, anal sex first, or report first two or three behaviors initiated at the same age, by sociodemographic characteristics (N=13,835)
There are striking differences across sociodemographic groups. Almost 40% of males reported initiating two or more behaviors within the same year, compared to only a quarter of females. Among those who staggered initiation, females were much more likely to have vaginal sex first, whereas similar percentages of males initiated oral-genital and vaginal sex first. Across race/ethnicity, non-Hispanic Asians, at 38%, had the largest representation in the no experience category. NH blacks were the least likely to have initiated more than one type of sexual behavior within the same year (17% versus 30 to 42% of other groups). Although a greater percentage of NH whites reported initiating vaginal sex first (26%) than initiating oral-genital sex first (18%), the difference is smaller than that for other race/ethnic groups. The difference is especially striking among NH blacks; only 7% first experienced oral-genital sex; 62% initiated with vaginal sex.
Higher percentages of respondents from all family structures reported having vaginal before oral-genital sex, although differences are smaller for respondents from two biological parent households. The latter were the least likely to initiate adolescent vaginal sex and the most likely to report no experience. Higher percentages of respondents with less educated parents had vaginal before oral-genital sex. Similar percentages of respondents with a college graduate parent reported initiating oral-genital and vaginal sex first. Initiating two or more behaviors within a year was relatively more common among earlier maturers while teens who matured later were more likely to report no experience.
Timing of initiation
Overall, average age at first vaginal sex was slightly younger (weighted mean = 15.5 years, standard error = 0.02) than age at first oral-genital sex (weighted mean = 15.8 years, standard error = 0.02). The average age of first anal sex, among those who had had anal sex by age 18, was almost a year older (weighted mean = 16.4 years, standard error = 0.06) and more variable (results not shown). Mean ages of initiation are listed by sociodemographic characteristics in ; with few exceptions, sociodemographics were associated with ages of initiating vaginal and oral-genital sex in multivariate OLS regression models. Respondents who were male, from a household structure other than two biological parents, or matured earlier were younger at first oral-genital experience. NH Asians were significantly older. For age at first vaginal sex, associations with family structure and pubertal timing were similar to those seen for oral-genital sex. However, NH blacks were younger than NH whites at first vaginal sex (versus a similar age at first oral-genital sex), and any parent education less than a college degree was associated with a younger age at first vaginal sex. Being male was the only characteristic associated with age at first anal sex.
Table 3 Mean age of initiation (and standard errors) of first oral-genital, vaginal, and anal sex, and coefficients (and standard errors) from OLS regressions of age at initiation of each behavior on sociodemographic characteristics, among respondents who report (more ...)
Comparisons between patterns in and indicate that behavior prevalence and timing of onset are not necessarily in tight synchrony. For example, NH blacks were a third as likely as NH whites to have had oral-genital sex by age 18 (), but mean age was the same among those who did initiate (). Similarly, adolescents whose parents had less than a high school diploma had the lowest prevalence (within this characteristic) of experiencing oral-genital sex (), but their average age of initiation did not differ from teens with college educated parents ().
Overlap in sexual experiences during adolescence
shows percentages of males and females who experienced different combinations of oral-genital, vaginal, and anal sex by age 18. The most common combination is to have both vaginal and oral-genital experience during adolescence (56% of males, and 51% of females). However for males, the next most common pattern is experience with all three types (11%), followed by vaginal sex only (8%), and oral-genital sex only (6%). For females, the most common pattern after the vaginal/oral-genital combination is vaginal sex only (19%), having all three types (9%), and oral-genital sex only (4%). The remaining patterns were uncommon for males and females.
Venn diagram illustrating the overlap among vaginal, oral-genital, and anal sex, by biological sex, by age 18.