A Statewide Survey of Age at First Intercourse for Adolescent Females and Age of Their Male Partners: Relation to Other Risk Behaviors and Statutory Rape Implications

In a statewide survey of a representative sample of adolescent girls in 8th–12th grades (N = 4201), information was obtained on age at first intercourse and age of their male partners. Excluding intercourse experiences where physical force was threatened or used, 31% had intercourse by age 15 and 45% by age 16. Contrary to the impression left by studies of teenage mothers, girls who first had sex between age 13 and age 15 or between age 16 and age 18 did not have a large percentage of much older partners (5 or more years older; 12 and 7%, respectively). The percentage of much older partners was higher, however, for girls who had sex in very early adolescence, ages 11–12 (34%). Much older male partners were associated with greater problem behaviors for girls who first had intercourse in very early adolescence (11–12), but less so for those who first had intercourse between age 13 and age 15 (truancy only) and not at all for those who first had intercourse at between 16 and 18. Regardless of partner's age disparity, earlier age at first intercourse during adolescence was associated with a greater number of other problem behaviors. The implications of these findings for recent calls to enforce statutory rape laws more stringently to reduce teenage pregnancy were discussed.     

Age of partners at first intercourse among Danish males and females

In 1984–1985 a representative sample of 286 Danish women (response rate = 75.3%) and 336 Danish men (response rate = 77.8%), ages 16–20 years, was interviewed about their first sexual intercourse. A cumulative frequency function was constructed and the median age at sexual debut was estimated at 16.8 years for both male and female. Generally the age difference between the partners at first intercourse was only a few years. However, the young women almost never reported their first sexual partner as younger than themselves. A cross-check was made of the information given by two homogeneous subsamples of the 47 young women and 80 young men who had their first sexual intercourse with a partner who was also a debutant. Self-reported age among the males differed significantly from the age of the first sexual partner as stated by the females in these subsamples. Therefore, there is bias in the reporting of age of partner at first intercourse. As the self-reported age at first sexual intercourse by young women agrees with the age of first partner as stated by young men, the bias seems to manifest itself predominantly as a systematic misreporting in the age of male partners of debutant females.This work supported by a research grant from Sygekassernes Helsefond.     

The relation between sexual activity among children during preadolescence and/or early adolescence and sexual behavior and sexual adjustment in young adulthood

This study examined whether current sexual behavior and sexual adjustment in a sample of 433 college students differed as a function of having engaged in sexual activity with other children during preadolescence (prior to age 13) and/or early adolescence (ages 13–15). Four groups were compared: subjects who only had an early adolescent sexual experience; subjects who had both preadolescent and early adolescent experiences; subjects who had no sexual experience with another child during either preadolescence or early adolescence. There were no significant differences between these groups on measures of incidence of premarital intercourse, age at first intercourse, number of different intercourse partners, sexual satisfaction, sexual arousal, or sexual dysfunctions. It was concluded that in general the simple occurrence or nonoccurrence of sexual activity among children during these developmental periods has little impact, either positive or negative, on later sexual adjustment during young adulthood. Some expections, depending on the specific types of childhood sexual activity involved, were noted.     

The determinants of sexual intercourse before age 16.

PURPOSE: To identify risk and protective factors for initiation of sexual intercourse before age 16 years at the level of the individual, family, and school. METHODS: A longitudinal study based on a cohort of 1020 people born in Dunedin, New Zealand in 1972/73 and followed up to age 21 years. Demographic characteristics of the sample were similar to the New Zealand population of that age, except that a smaller proportion (3%) were Maori or Pacific Island Polynesian. Information on individual, family and school factors was collected by interview with parents at ages 3, 5, 7 and 9 years and then by postal questionnaire two-yearly up to 15 years. Subjects were assessed two-yearly from age 3 years and interviewed about their behaviours and ambitions at ages 11, 13, and 15 years. Questions about age at first intercourse were asked by computer at age 21 years. Multivariate logistic regression was used to model associations with age of first intercourse less than 16 years. RESULTS: Data on age at first intercourse were available for 926/1020 (91%) of surviving members of the cohort assembled at age 3 years. Overall 27.5% of males and 31.7% of females reported sexual intercourse before age 16 years. In multivariate analyses the independent predictors for early sexual initiation for males were: not having outside home interests at age 13 years, no religious activity at age 11 years, not being attached to school at age 15 years, a low reading score, and a diagnosis of conduct disorder in early adolescence. For females, independent predictors were: socioeconomic status in the middle range, mother having her first child before age 20 years, IQ in the middle range, not being attached to school, being in trouble at school, planning to leave school early, cigarette smoking and higher self-esteem score. CONCLUSIONS: Individual and school factors appear to be more important than family composition or socioeconomic status in the decision to have sexual intercourse before age 16 years. The lowering of age at first intercourse may be partly a cohort effect related to high rates of teenage childbearing in the mothers' generation, and to changes in social acceptability of early sexual behaviour.     

Correlates of Increased Sexual Satisfaction

Comparisons of nationally representative survey data of the population ages 18–54 years in 1971 (N = 2252) and 1992 (N = 1718) from Finland show that sexual satisfaction has greatly increased particularly among women. Some predictors of sexual satisfaction of men and women are examined on the basis of the 1992 survey data on people ages 18–74 years (N = 2250). Correlations between social background factors, sexual ideas and assertiveness, optional relationships, sexual practices, orgasm, and satisfaction with sexual intercourse were calculated. To control the simultaneous effect of the variables explaining satisfaction, path analyses were conducted. Results show that young age, a sexually unreserved and a nonreligious childhood home, early start of sexual life, high education, sexual assertiveness, considering sexuality important in life, reciprocal feeling of love, use of sex materials, frequent intercourse, many-sided (versatile) sexual techniques, and frequent orgasm correlate with finding sexual intercourse pleasurable. There were some gender differences in the connections between the independent factors and satisfaction with coitus. The importance of sexuality in life, love, and the use of sexual materials were connected directly to physical sexual satisfaction among men but only indirectly among women. For women, but not for men, young age and early start of sexual life correlated with enjoyment of intercourse. The greater sexual dissatisfaction of women compared to men, which still prevails, may be due to their late start of sexual life, conservative sexual attitudes, unimportance of sexuality in life, lack of sexual assertiveness, and use of restricted sexual techniques. The emancipation of women may change these ideas and practices of women. This might lessen the gender gap in physical sexual satisfaction.     

Psychosexual development,maternalism, nonpromiscuity,and body image in 15 females with precocious puberty

Fifteen females with a history of idiopathic sexual precocity were selected without known sampling bias. They had been followed for as long as 18 years. They showed various behavioral characteristics as a group, but were also individually unique. If the IQ permitted, they benefited socially from school acceleration. Left to their own devices, the majority preferred friends nearer to them in physique age rather than chronologic age. Play interests, though influenced by the age of playmates, showed no features unique to the precocious onset of hormonal puberty. About half of the girls had occasional moody or depressed spells and wanted to be left alone. Maternalistic interests were strongly represented; only one girl was a tomboy. Masturbation and sexual play in childhood were rarely confirmed, and in no instances were totally contrary to family or community mores. No consistent progression of erotic dream content was discerned. Dreams of having a baby were rare, but antedated intercourse dreams, which were also rarely reported and did not include sensations of climax. Whereas the youngest age of having a serious boyfriend was 8 years, and the youngest age of intercourse, 11, the majority of girls did not report romantic and sexual involvements before the middle teenage years or later. In the three instances of marriage, the youngest was at age 21. Motherhood has so far been achieved by only one patient. She delivered her first child at age 11. The visible appearance of early sexual development and early advanced statural growth created a problem in childhood human relationships for most of the girls, regardless of what they said, and regardless of their skill or ineptitude in handling it. They all benefited even from minimal counseling, as did their parents. Early appearance of physical sexual development does not automatically lead to premature engagement in erotic activity or promiscuous sexual behavior. Such activity and behavior require appropriate experience and facilitating knowledge of erotic opportunities.Supported in research by Grant 5K03-HD18635 and Grant 2R01-HD00325, USPHS.     

Changes in the sexual life of czechoslovak women born between 1911 and 1958

In the course of 26 years the authors have collected sexual history data via interview on 1779 gynecological patients, aged 20 to 40. All had been married for at least 1 year. None sought consultation for sexological difficulties. According to the year of birth they were divided into five subgroups from 1911–1920 up to 1951–1958. During that time the average age of women at first sexual intercourse decreased from 20.75 years to less than 18 years. The percentage of orgastic women grew from 31% to 79%, and high coital activity in marriage rose from 40% to 86%. There was a decreasing number of women who came from a family of more than six children. The percentage of women who had secondary or college education increased. A significant acceleration of menarche was found only in the subgroup of women born after 1950.     

Trends in lifestyle coronary risk factors in the Danish MONICA population 1982–1992

Myocardial infarction incidence rate declined 3–5% per year during 1982–1992 in the Danish study population of the WHO MONICA Project. We examined whether smoking habits, alcohol intake, dietary habits and physical activity levels changed in the population during the same period.Data from 6695 men and women of ages 30, 40, 50 and 60 y, examined in 1982–4, in 1986–7, and in 1991–2, were analysed to estimate trends. A summary healthy eating index and six scores derived by factor analysis were used to analyse food frequency data.The percentage of smokers declined 1.6% per year in men, and 1.0% per year in 30-, 40- and 50-y-old women, but increased 0.9% per year in 60-y-old women. The percentages of heavy cigarette smoking men and women nevertheless remained constant and close to 30%. Total alcohol intake declined among 30-y-olds, but appeared constant in other age groups. However, among 60-y-old men and among women over 30, the percentage of wine-drinkers rose from 6–11% in 1982–4 to 9–18% in 1991–2. Only 60-y-old men became more physically active at work and only 30-y-old women more so in leisure times. The percentage of individuals with a low healthy eating index decreased and the percentage with a high index increased. More importantly, dietary factor scores showed trends suggesting that very profound and potentially beneficial changes in dietary habits occurred.Lifestyle in the DAN-MONICA population changed in several ways that may have contributed to the declining incidence of myocardial infarction during the 1980s. Public Health (2002) 116, 81–88     

Sex in Australia: first experiences of vaginal intercourse and oral sex among a representative sample of adults

Objective To describe the characteristics of Australian adults' first vaginal intercourse and contraceptive use on that occasion, as well as first oral sex. Method Computer‐assisted telephone interviews were completed by a representative sample of 10,173 men and 9,134 women aged 16–59 years. The overall response rate was 73.1% (69.4% men, 77.6% women). Respondents indicated their age at first vaginal intercourse (if ever), the partner's age, their relationship to their partner, the duration of the relationship before first intercourse, and what contraception (if any) was used. Respondents also indicated their age when they first had oral sex. Results : For men, the median age at first intercourse declined from 18 among men aged 50–59 to 16 for men aged 16–19. For women the decline in median age was from 19 to 16. For women born between 1941 and 1950 the difference in median age at first vaginal intercourse and subsequent first oral sex was six years but for women born between 1981 and 1986 the difference in medians was one year. For men, a similar convergence was observed. Contraceptive use at first intercourse has increased significantly, from less than 30% of men and women in the 1950s to over 90% in the 2000s. For men, first intercourse before age 16 was significantly associated with greater numbers of lifetime and recent sexual partners, ever having paid for sex and having had a sexually transmitted infection (STI), and for women, with greater numbers of lifetime and recent sexual partners, ever having been paid for sex and ever having had an STI. Conclusion Sex education should be given so that all young people have information about contraception and disease prevention before they begin their sexual careers.     

Kinsey revisited,part I: Comparisons of the sexual socialization and sexual behavior of white women over 33 years

This research compared data from two studies of women's sexual behavior—one conducted in the 1940s, the other in the 1980s. The first sample included 3952 white women, ages 18 to 36, drawn from the larger sample of women who participated in the original Kinsey study. The second comprised 122 white women, in the same age range, who had taken part in a recent study of sexual socialization and experiences among women in Los Angeles County, CA. Log-linear analyses were used to control for differences between the samples on age, education, and marital status. Comparisons were conducted in the areas of childhood family characteristics; sexual socialization and education; sexual behavior in childhood, adolescence, and adulthood; contraceptive practices; and child sexual abuse. Results tended to reflect changes that have taken place in society and in patterns of sexual behavior. Differences in sexual socialization pointed to the increased role of the media and the schools and to more relaxed attitudes about nudity in the home. Shifts in sexual behavior were particularly dramatic. As compared to women in the Kinsey sample, the newer subjects began intercourse earlier, were less likely to have a fiance or husband as their first partner, reported a higher number of sexual partners, and participated in a broader range of sexual behaviors. Contraceptive practices differed considerably, especially among never-married women. Women in the new study were also more likely to report instances of child sexual abuse. Methodological and social factors contributing to the findings are discussed.This research was supported by the Center for the Prevention and Control of Rape, NIMH, MH 33603 and through a Research Scientist Career Development Award (MH 00269), to the first author.     

Use of contraception and use of family planning services in the United States: 1982-2002

OBJECTIVE: This report presents national estimates of contraceptive use and method choice based on the 1982, 1995, and 2002 National Surveys of Family Growth (NSFG). It also presents data on where women obtained family planning and medical services, and some of the services that they received. METHODS: Data were collected through in-person interviews with 12,571 men and women 15-44 years of age in the civilian noninstitutional population of the United States in 2002. This report is based on the sample of 7,643 women interviewed in 2002. The response rate for women in the study was about 80 percent. RESULTS: The leading method of contraception in the United States in 2002 was the oral contraceptive pill, used by 11.6 million women; the second leading method was female sterilization, used by 10.3 million women. The condom was the third-leading method, used by about 9 million women and their partners. The condom is the leading method at first intercourse; the pill is the leading method among women under 30; and female sterilization is the leading method among women 35 and older. More than 98 percent of women 15-44 years of age who have ever had sexual intercourse with a male (referred to as "sexually experienced women") have used at least one contraceptive method. Over the 20 years from 1982 to 2002, the percent who had ever had a partner who used the male condom increased from 52 to 90 percent. The proportion who had ever had a partner who used withdrawal increased from 25 percent in 1982 to 56 percent in 2002. Another important measure of contraceptive use is use at the first premarital intercourse: before 1980, only 43 percent of women (or their partner) used a method of birth control at their first premarital intercourse. By 1999-2002, the proportion using a method at first premarital intercourse had risen to 79 percent.     

Correlates of Heterosexual Behavior Among 23–87 Year Olds in Denmark and Sweden, 1992–1998

Correlates of heterosexual behavior, with a particular focus on early and high sexual activity, anal intercourse, prostitute visits, and HIV test activity, were studied. Telephone interviews were conducted with 852 randomly chosen persons who participated as controls in nationwide case–control studies of anogenital cancers in Denmark and Sweden, 1992–1998. While partner numbers and the practice of anal intercourse increased, age at sexual debut declined by 4–5 years (p < 0.001) and the maturation interval between menarche and first coitus halved (from 7 to 3 years, p < 0.001) between persons born in or before 1920 and those born in or after 1960. Women having high sexual activity were more often tested for HIV than less sexually active women, but men visiting prostitutes and those with prior STDs were not HIV tested more than other men. The increasing practice of anal intercourse, particularly among women with many partners, deserves attention, since this practice may erroneously be considered a safe sexual activity. Along with their partners, men with a history of STDs and those visiting prostitutes should be targeted in future safe sex campaigns, since these men appear to be inadequately HIV tested.     

Delayed Childbearing by Education Level in the United States, 1969–1994

Objectives. Advanced maternal age at first birth, but not at subsequent births, may have detrimental health implications for both mother and child, such as a poor birth outcome and an increased risk of maternal breast cancer. However, positive outcomes may also result such as an improvement in economic measures and offspring's performance on cognitive tests. Research has indicated that women increasingly are delaying their first births beyond the early twenties, but the recent trends in socioeconomic disparity in age at first birth, and the implications for public health, have not been well described. Method. This study used national birth certificate data for 1969–1994 to examine age at first birth by maternal education level. Current Population Survey data were also used to examine changes over time in age and educational distribution among women of childbearing age. Results. Age at first birth increased during the time period. Median age at first birth increased from 21.3 to 24.4 between 1969 and 1994, and the proportion of first-time mothers who were age 30 or older increased from 4.1% to 21.2%. Age at first birth increased rapidly among women with 12 or more years of education; nearly half (45.5%) of college graduate women who had their first birth in 1994 were age 30 or older, compared with 10.2% in 1969. However, little change was observed among women with fewer than 12 years of education; among those with 9–11 years of education, only 2.5% of first births in 1994 occurred at age 30 or older. Conclusions. The trend toward postponed childbearing has occurred primarily among women with at least a high school education. Health services use, such as infertility treatment and cesarean section, may increase as a result of delayed childbearing among higher educated women. Future examinations of the association between maternal age at first birth and health outcomes may need to take greater account of socioeconomic differentials.     

Childhood family disruption and adult height: is there a mediating role of puberty?

Background and objectives: Childhood family background is known to be associated with child growth and development, including the onset of puberty, but less is known about the influence of childhood family disruption on outcomes in later life. Given the associations between early family disruption and childhood development, we predicted that there may be long-term health-relevant consequences of childhood disruption.Methodology: Using data from a large US interview sample (n = 16 207), we test if death or divorce of parents, at different childhood periods, was associated with adult stature, and whether age at puberty mediated this relationship, for men and women.Results: Men: parental death and divorce during early childhood was associated with shorter adult height, and later puberty. Later puberty was associated with shorter adult height. Path analyses demonstrated that the relationship between parental divorce and height was completely mediated by age at puberty; although parental death was only partially mediated by age at puberty. Women: the father’s death during early childhood was associated with earlier puberty, which was in turn associated with shorter adult stature. The relationship between paternal death and height is entirely mediated by age at puberty; no evidence of a direct relationship between childhood family disruption and adult height.Conclusions: Early childhood familial disruption is associated with shorter height for men, and is partially mediated by later puberty. For women, the relationship between father’s death, and height was completely mediated by earlier puberty. These findings indicate that disruption during childhood can have long-reaching health repercussions, particularly for boys.     

Reexamining factors predicting Afro-American and white American women's age at first coitus

Research identifying factors associated with ethnic differences in first coitus has been limited by methodologies and samples used. This study reexamines ethnic differences in Afro-American and white American women's age of first coitus. Demographic, socialization, and decision-making factors were examined in a series of multiple regression analyses, with the prevalence of women's child sexual abuse incidents, in order to identify variables that best predicted age of first coitus. The subjects were a multiethnic community sample of 248 women, 18 to 36 years of age, residing in Los Angeles County. Their demographic characteristics were comparable on education, marital status, the prevalence of children, and income. The results indicated that women's perceptions of their parents as more influential than peers during adolescence, and being in love and ready for sex were predictors of an older age at first intercourse. Ethnicity was not significantly associated with the strongest predictors or with first coitus. Factors that best predicted first coitus were also similar for both ethnic groups. The findings suggest that in order to examine the role of ethnicity in first coitus, differences in demographic characteristics found between black and white samples need to be controlled. Similarly, multiethnic research should include variables that are relevant to both ethnic groups, as well as abusive sexual experiences, in order to understand the multiplicity of factors predicting age at first intercourse.This research was funded by the Center for Prevention and Control of Rape, NIMH Grant, R01 MH33603 and through a Research Scientist Career Development Award, K01 MH00269.     

Early childhood nutrition, education and fertility milestones in Guatemala

Data on fertility milestones were collected in 1994 and linked to information collected in a trial conducted in eastern Guatemala between 1969 and 1977, to examine whether early childhood nutrition was associated with the timing of fertility milestones. In the original trial, two pairs of villages were randomly allocated to receive either a high energy, high protein supplement (Atole) or a low energy, no-protein supplement (Fresco). Mean age at follow-up was 23.47 y (n = 240). About 62% of women had experienced first birth (median age at first birth = 19.83 y). The median intervals from menarche to first intercourse and from first intercourse to first birth were 5.67 and 0.95 y; they were 1.68 and 0.06 y shorter, respectively, for the Atole group than for the Fresco group. Women who had received Atole in utero and/or during early childhood experienced earlier milestones even after adjusting for socioeconomic status (SES), education and age at the prior event. Median age at first birth was 1.17 y earlier for the Atole group. Better growth during early childhood (not severely stunted) led to earlier milestones (median age at first birth was 1.04 y earlier), primarily among women with illiterate fathers. Completion of primary school significantly delayed fertility milestones; the median age at first birth was 4.27 y later for those who completed primary school compared with those who did not (P < 0.05). In sum, improved nutrition during early childhood results in earlier fertility milestones, but the effects of schooling in delaying fertility milestones are greater in magnitude. Intervention programs that improve early childhood nutrition should be accompanied by investments in education that ensure that girls complete primary school.     

Sexuality and aging in male veterans: A cross-sectional study of interest,ability, and activity

To gather data on sexuality, specifically in male veterans, and to test the hypothesis that aged males remain interested in sexual intercourse yet suffer from erectile failure, veterans age 30 to 99 were surveyed. The mailed survey had 88 questions and was pretested on young potent males and aged impotent males. From 1031 randomly selected subjects, there were 806 replies: 427 completed surveys, 247 refusals, and 132 who were too ill to participate (225 failed to reply). Among responders, sexual interest declined from a mean of 4.4/5 (4 = very interested, 5 = extremely interested) in men age 30–39 years to 2.0/5 (2 = slightly interested) in men age 90–99 (p < 0.0001). Vaginal intercourse was consistently the preferred sexual activity; however, intercourse frequency was diminished from a mean of once per week in 30- to 39-year-olds to once per year in 90- to 99-year-olds (p < 0.0001). Frequency, rigidity, and duration of erections were less in aged compared to younger cohorts (p < 0.0001). With these facts in mind, further research to bridge the libido-potency gap is warranted.This work was completed at the Hunter Holmes McGuire Veteran's Affairs Medical Center, Richmond, Virginia.     

The Association between Maternal Smoking during Pregnancy and Childhood Obesity Persists to the Age of 9–10 Years

Background

We previously reported that a number of factors related to maternal lifestyle during early pregnancy, including smoking, are associated with childhood obesity at 5 years of age. In the present study, we investigated whether the association with maternal smoking persisted to the age of 9–10 years.

Methods

The study population comprised children born between April 1, 1991 and March 31, 1999, and their mothers. The dependent variables—childhood overweight and obesity at 5 and 9–10 years of age—were defined according to internationally acknowledged cut-off values. Maternal smoking during early pregnancy was used as the independent variable.

Results

Mothers who completed a specifically designed questionnaire gave birth to a total of 1644 infants during the study period. Anthropometric data were collected from 1302 of these children during medical checkups at 9–10 years of age (follow-up rate: 79.2%). Maternal smoking during early pregnancy was associated with obesity in 9- to 10-year-old children (adjusted odds ratio, 1.91; 95% confidence interval, 1.03–3.53). However, the point estimates at the age of 9–10 years were considerably lower than those at the age of 5 years.

Conclusions

Our results suggest that fetal environment, including exposure to maternal smoking, continues to be associated with childhood obesity at the age of 9–10 years.Key words: smoking, pregnancy, life styles, obesity, fetal programming     

Repeat Abortions in New York City, 2010

This study aims to describe factors associated with the number of past abortions obtained by New York City (NYC) abortion patients in 2010. We calculated rates of first and repeat abortion by age, race/ethnicity, and neighborhood-level poverty and the mean number of self-reported past abortions by age, race/ethnicity, neighborhood-level poverty, number of living children, education, payment method, marital status, and nativity. We used negative binomial regression to predict number of past abortions by patient characteristics. Of the 76,614 abortions reported for NYC residents in 2010, 57 % were repeat abortions. Repeat abortions comprised >50 % of total abortions among the majority of sociodemographic groups we examined. Overall, mean number of past abortions was 1.3. Mean number of past abortions was higher for women aged 30–34 years (1.77), women with ≥5 children (2.50), and black non-Hispanic women (1.52). After multivariable regression, age, race/ethnicity, and number of children were the strongest predictors of number of past abortions. This analysis demonstrates that, although socioeconomic disparities exist, all abortion patients are at high risk for repeat unintended pregnancy and abortion.     

Sexual Timetables for Oral-Genital,Vaginal, and Anal Intercourse: Sociodemographic Comparisons in a Nationally Representative Sample of Adolescents

Objectives. We documented the prevalence and relative timing of oral-genital, vaginal, and anal intercourse during adolescence and examined whether these timetables varied by sociodemographic factors.Methods. We used data from almost 14 000 Wave IV respondents to the National Longitudinal Study of Adolescent Health to generate prevalence estimates for adolescents who reached age 18 years by 2001 and logistic and ordinary least squares regression to examine sociodemographic correlates of sexual patterns.Results. One in 5 adolescents did not engage in any of these sexual behaviors by age 18 years. More than two thirds reported vaginal or oral-genital sexual activity, but only about half experienced both. One in 10 reported anal intercourse experience. A third initiated 2 or more behaviors within a 1-year period. In longer timetables, vaginal intercourse was more often initiated first. Most sociodemographic characteristics examined were uniquely associated with prevalence and sexual timing.Conclusions. Diversity in patterns of sexual initiation occurring in the 1990s underscores the ongoing need for comprehensive and nuanced examinations of adolescent sexual trajectories and their implications for sexual health in more recent cohorts.Sexual behavior patterns have evolved significantly since the “first sexual revolution” of the 1920s.1 Fewer than 10% of individuals born early in the 20th century had sex by age 18 years, compared with more than 50% of persons born between 1968 and 1973.2 Of individuals 15 to 44 years old in 2002, 75% had had premarital vaginal intercourse by age 20 years3; almost 90% of individuals 18 to 27 years old in 2001 had had premarital vaginal intercourse.4Most adolescent sexuality research focuses exclusively on vaginal intercourse. Two cross-sectional US national surveys routinely measure vaginal intercourse in adolescent samples. Estimates from the Centers for Disease Control and Prevention’s 2009 Youth Risk Behavior Survey indicate that approximately 60% of male and 65% of female high-school seniors have had vaginal intercourse.5 Similarly, in the 2006 to 2008 National Survey of Family Growth (NSFG), 66% of men and 62% of women aged 18 and 19 years had had vaginal intercourse.6By contrast, estimates of adolescent oral-genital and anal intercourse experience vary widely, probably because most, except NSFG figures, are based on smaller community samples.7–10 During the 1980s and 1990s, estimates of adolescent oral-genital sexual activity ranged from 35% to 66%. In the 2006 to 2008 NSFG, 70% of men and 63% of women aged 18 to 19 reported oral-genital sexual activity.6 Community sample prevalence estimates of adolescent anal intercourse range from 20% to 32%.10 Recent NSFG data indicate that almost 17% of men and 15% of women aged 18 to 19 years have ever had anal intercourse.6 The Youth Risk Behavior Survey does not ask about oral-genital or anal intercourse.The order of initiating oral-genital and vaginal intercourse is of interest because initiating oral-genital sexual activity first, which carries lower risk of sexually transmitted diseases (STDs) than does vaginal or anal intercourse, could substitute for vaginal and anal intercourse, postpone their onset, or hasten the transition to coital or anal experience. Community sample estimates of initiating oral-genital intercourse first range from 14% to 50%.7–9,11,12 Some analyses indicate that “vaginal virgins” are less likely to have had oral-genital intercourse than are “vaginal nonvirgins,” implying that vaginal intercourse typically occurs first.10,13,14 However, about half of male and female respondents aged 15 to 24 reported that they had oral-genital before vaginal intercourse in the 2006 to 2008 NSFG data.6 The NSFG does not measure the amount of time separating oral-genital and vaginal initiation. There has been less investigation of anal intercourse, but given its low prevalence (10% of respondents aged 15–19 years in the 2006–2008 NSFG),6 if anal intercourse is initiated during adolescence, it will typically occur last.Timing of first sexual experience may have implications for the sexual sequence and pace that follow.14 There has been extensive research on the timing of first vaginal intercourse in particular. In the United States, the average age at first vaginal intercourse is about 17 years.15 Mean ages at initiation of oral-genital and anal intercourse have not been reported for current national data.Documenting variation and typicality in the order and timing of life experiences—including sexual experience—across cohorts is important because they may differentially affect physical and emotional health within and across historical time.16 For example, initiating intimate behaviors (e.g., vaginal intercourse) before less intimate ones (e.g., kissing) has been linked to inconsistent use of contraception.17 Findings suggest differential psychosocial implications of oral-genital and vaginal intercourse,18,19 which may make order of initiation important. Compared with adolescents with vaginal intercourse experience (with or without oral-genital sexual experience), adolescents who have had only oral-genital intercourse are less likely to feel guilty or used or to get into trouble with parents because of sexual activity. However, they are also less likely to experience sexual pleasure or to report feeling good about themselves.18 Early coitus is also linked to higher likelihood of sexual risk taking, including inconsistent condom use, more sexual partners, and, at least during adolescence, a higher likelihood of STDs.20–23 Heterosexual anal intercourse is also a marker for sexual risk taking.24In summary, despite potential implications for sexual health and general well-being, few studies have documented the typicality of sexual timetables for multiple behaviors, and much of the available information is based on relatively small and geographically limited samples. To date, only NSFG data from 2002 forward allow estimates of adolescent oral-genital and anal intercourse for a nationally representative sample. Although a valuable resource, NSFG data do not include ages at initiation of noncoital behavior, limiting opportunities to evaluate implications of sexual timing.The current study provided unique information about the timing (age at initiation) of oral-genital, vaginal, and anal intercourse and order of initiation for adolescents in grades 7 through 12 in the 1994 to 1995 school year. Documenting sexual timetables during adolescence provides a foundation for examining developmental implications of patterns and offers a point of reference to examine historical changes. We used data from the National Longitudinal Study of Adolescent Health (Add Health) to examine the

• prevalence of vaginal, oral-genital, and anal sexual experience during adolescence and whether prevalence varies by age cohort, biological sex, pubertal timing, race/ethnicity, family structure, and parent education;
• typicality of the earliest behavior (i.e., which is initiated first) across groups defined earlier;
• average timing (age) at initiation of oral-genital, vaginal, and anal intercourse and whether timing varies by groups defined earlier; and
• overlap in experience of oral-genital, vaginal, and anal intercourse during adolescence and whether overlap varies by biological sex.