Sample

The data for this study were collected between June 1995 and April 1996 as part of the National Sexual Health Survey, conducted by the Center for AIDS Prevention Studies, University of California, San Francisco.³⁹

The study population (n = 8466) included English-or Spanish-speaking adults 18 years or older who resided (in housing units other than those located on military bases) in the 48 contiguous states. Participants were contacted and interviewed via random-digit dialing. The overall cooperation rate was 65%

• (see Ruiz et al.³⁹ for a full description of the sampling and data collection procedures).

Forty-eight percent of the participants were men (Table 1).

Table 1

Sample Characteristics, Mean Age at First Sexual Intercourse, and Percentage of Participants Whose Initial Sexual Intercourse Occurred After Marriage: National Sexual Health Survey, 1995–1996

• Note. Data were weighted. TQ1<<AU: Correct? College or less would include the category high school or less.>>

• The majority of the sample was White (74%).
• Mean ages were 43.3 years for men and 45.5 years for women; almost 50% of the participants were younger than 40 years.
• Sixty-five percent of men and 59% of women were involved in intimate sexual relationships (57.9% of men and 51.0% of women were married).

Timing of participants’ first sexual intercourse was categorized as early, normative, or late in comparison with peers of the same gender and with the same racial/ethnic and educational background.

To categorize participants, we initially subtracted their age at first sexual intercourse from the mean age for their respective subgroup. Those with scores in the first and fourth quartiles of the resulting difference score distributions for their subgroups were classified as “late” and “early” starters, respectively.

Consequently, 25% of both men and women were categorized as having had an early or late start, and 50% were categorized as having had a normative start. Mean ages for early, normative, and late starters according to gender, racial/ethnic background, and educational level are shown in Table 2.

Table 2

Mean Age at First Sexual Intercourse Among Early, Normative, and Late Starters, by Sociodemographic Characteristics: National Sexual Health Survey, 1995–1996

• Note: Participants with scores in the first and fourth quartiles of their subgroups were classified as late and early starters, respectively.

In addition, we categorized participants as having had their first sexual intercourse before or after marriage by comparing age at first sexual intercourse with age at marriage

• (if these ages were identical, participants were categorized as having had their first sexual intercourse after marriage).

We were able to classify 40.1% of men and 34.4% of women in this way. As a result of skip patterns in the survey, we were not able to determine timing of first sexual intercourse in relation to marital status among individuals who had been married more than once or were no longer married. These men and women were systematically different from those we were able to classify, specifically in terms of outcome variables (as described subsequently). Among the individuals we were able to classify, 13.6% of men and 36.1% of women had engaged in their first sexual intercourse after marriage (Table 1).
 

Measures

We examined several factors indicative of sexual risk:

• high number of sexual partners and history of sexual intercourse with a risky sexual partner
  (e.g., injection-drug-using or HIV-positive partner) in the preceding 1 and 5 years,
• frequent use (about half of the time or more frequent) of drugs such as alcohol or marijuana before intercourse with at least 1 partner during the preceding 12 months,
• denial of HIV risk
  (i.e., one’s categorical belief that one is not at risk for HIV or other STIs, assessed on a 2-item scale [Cronbach ? =0.79]),
• history of an STI or of HIV-positive status as an indication of risky behavior, and
• negative attitudes toward condoms
  (assessed on a 17-item scale [Cronbach ? =0.74]).

Also, we explored aspects of participants’ intimate relationships and sexual functioning, including

• their satisfaction with their current sexual relationship
  (very satisfied vs somewhat satisfied and somewhat or very dissatisfied),
• the solidity of their relationship
  (assessed on a 3-item scale [e.g., “We can count on each other for help in solving problems”; Cronbach ? = 0.69]), and
• any problems they experienced with becoming sexually aroused, achieving or maintaining erections, or reaching orgasm (in the preceding 12 months).
• Finally, we assessed participants’ general health via 10 questions focusing on the presence of physical health and emotional problems in the preceding 4 weeks and whether these problems, if present, affected participants’ daily functioning (sum score ranging from 0 [poor health] to 10 [good health] based on number of “no” responses).
   

Data Analysis

We conducted linear and logistic regression analyses to examine relationships between timing of first sexual intercourse and sexual health outcomes.

We controlled for the following potentially confounding factors:

• race/ ethnicity,
• educational level,
• place of residence while growing up,
• religiosity,
• migration status,
• age (as an indicator of potential cohort effects),
• history of nonconsensual sexual experiences,
• first orgasm as a solo or social experience, and
• any other sexual involvement before first sexual intercourse.

Analyses were conducted separately for men and women, and data were weighted to ensure that the sample would be representative of the adult US population.³⁹ Because our study was exploratory, we established P<.10 as the significance level and did not correct for multiple comparisons.

Timing of first sexual intercourse was associated with several sexual risk factors in the case of both men and women (Table 3).

Table 3

Independent Effects of Sexual Intercourse Initiation Patterns on Long-Term Health Outcomes: National Sexual Health Survey, 1995–1996

• Note. OR= odds ratio; STI = sexually transmitted infection.
  Odds ratios were adjusted for socio-demographic and contextual factors, including non-consensual sexual experiences, and were from logistic regression analyses. See “Methods” section for more information about effects.
  [a] Comparison with same-gender peers of the same racial/ethnic background who began at a normative age.
  [b] Comparison with participants whose first sexual intercourse occurred before marriage.
  *P < .10; **P < .05; ***P < .01.

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Men and women who had had an early start reported more sexual partners in the past year and the preceding 5 years and were more likely to have had sexual intercourse with at least 1 risky partner in the preceding 1 and 5 years. Early starters also were more likely to have had sexual intercourse under the influence of alcohol or drugs in the preceding year.

We found the opposite effect among late starters, although not all differences were significant. Late starters were less likely to have had at least 1 risky sexual partner in the preceding 1 year and the preceding 5 years.

The differences observed between individuals whose first sexual intercourse had occurred before marriage and those whose first sexual intercourse had occurred after marriage were similar to the differences observed between early and normative starters. Men and women whose first sexual intercourse had occurred after marriage reported fewer sexual partners and were less likely to have had sexual intercourse with a risky partner in the preceding 5 years. Women whose first sexual intercourse had occurred after marriage were less likely to have had sexual intercourse under the influence of alcohol or drugs.

Attitudes toward HIV risk transmission were also associated with timing of first sexual intercourse. Both men and women with a late start were less likely to deny transmission risks than were men and women whose first sexual intercourse had occurred at a normative age. Men whose first sexual intercourse had occurred relatively early were more likely than were men who had started at a normative age to deny risk of transmission.

Attitudes toward condoms were not related to timing of first sexual intercourse, except in the case of women whose first sexual intercourse had occurred at an early age; these women had more negative attitudes toward condoms than did women who had started at a normative age.

In line with the differences just described, early starters were more likely than were those who had started at a normative age to have a history of an STI, whereas late-starting women were less likely than were those who had started at a normative age to have such a history. Women, but not men, whose first sexual intercourse had occurred after marriage were less likely to have a history of an STI.
 

Intimate Relationships, Sexual Functioning, and General Health

Relationship solidity was not associated with timing of first sexual intercourse, with the exception of men whose first sexual intercourse had occurred after marriage

• (it should be noted that these men represented a very small proportion of the overall sample);

these men rated their marital relationship as more solid than men whose first sexual intercourse had occurred before marriage. The percentages of men and women who reported being very satisfied with their current sexual relationship did not differ according to timing of first sexual intercourse.

The findings in regard to sexual functioning were intriguing. In comparison with men whose first sexual intercourse had occurred at a normative age, men whose first sexual intercourse had occurred at relatively early and late ages more frequently reported having had problems associated with becoming sexually aroused, achieving and maintaining an erection, and reaching orgasm.

We did not find significant differences among women in frequency of problems associated with arousal and orgasm. The only exception was women whose first sexual intercourse occurred relatively late; in comparison with normative starters, these women more frequently reported problems related to sexual arousal.

Whether initial sexual intercourse occurred before or after marriage was not associated with frequency of sexual problems, with a single exception: men whose first sexual intercourse occurred after marriage were more likely to report problems with achieving and maintaining an erection.

Ratings of general health status were lower among men whose first sexual intercourse had occurred at an early age than among men whose first sexual intercourse had occurred at a normative age. In all other cases, timing of first sexual intercourse was not associated with general health status.
 

Non-consensual Experiences

History of non-consensual sexual experiences was independently associated with poorer sexual health outcomes (data not shown). Among women, non-consensual sexual experiences, regardless of whether they preceded or followed initial consensual intercourse, were associated with almost all of the outcomes assessed in this study.

Among men, non-consensual sexual experiences primarily were associated with sexual problems and risk factors such as high number of sexual partners and STI history if these experiences had occurred after their first sexual intercourse. When non-consensual experiences had occurred before men’s first consensual sexual intercourse, there were fewer long-term negative health outcomes; non-consensual experiences before first consensual sexual intercourse were independently associated only with history of risky partners in the preceding 5 years, problems with orgasm, and (in a negative direction) general health status.
 

Additional Analyses

In addition to the analyses described in the preceding sections, we conducted analyses in which we excluded men and women with a history of non-consensual sexual experiences as well as those who identified themselves as gay, lesbian, or bisexual (this group was too small to analyze independently). These additional analyses produced patterns of results virtually identical to those already reported.

Discussion