Most respondents (92.6%) self-identified as heterosexual, with 2.0% as lesbian and 1.2% as bisexual (Table 1). Sexual activity was reported with men only by 71.8%, with women only by 2.1% and with neither men nor women by 22.3%. Three-fourths of the cells in Table 1 contain respondents, indicating several combinations of answers to the two items and a potential limitation of measuring only one dimension of sexual orientation. About three-fourths (77%) of self-identified heterosexual respondents reported sexual activity with men only; a similar percentage (79%) of self-identified lesbian respondents reported sexual activity with women only. Virtually all respondents who self-identified as lesbian reported sexual activity with women only or with neither men nor women (89/90). Among respondents who reported sexual activity with women only, 74% self-identified as lesbian, 15% self-identified as bisexual, and 11% self-identified as heterosexual.
Sample sizes vary for comparative analyses of lesbians and heterosexual women across the three definitions of lesbian/heterosexual (Table 3). The sample size for the lesbian group ranges from 90 to 115, with the larger sample size for the combined definition based on identity and behavior. One-fourth of respondents cannot be classified using only sexual behavior, because a current or recent time frame was used. A few subjects cannot be classified because of missing data for one or both items.
The 25 additional respondents classified as lesbian by using the combined identity and behavior definition, compared with the identity definition, reported current sex with women but did not self-identify as lesbian (14 as bisexual and 11 as heterosexual). These 25 respondents differ from the 90 self-identified lesbian respondents on marital status (Table 4): they are more likely to be ever married or currently married. These two respondent groups of lesbians do not differ much by age, race, ever having been pregnant, parity, being currently coupled, number of children (biological and other), political affiliation, or self-rated health (Table 4).
The rate of subject nonresponse to the WPHS survey appears unaffected by sexual orientation questions, because it is comparable with that of other physician surveys without such questions. 13 Low item-nonresponse rates on sexual orientation dimensions, as observed in WPHS, have also been reported in two large longitudinal studies of women’s health that use self-administered questionnaires: the NHS-2 (N = 117,000) and the WHI (N = 170,000).
In the NHS-2 in 1995, more than 99% of female respondents reported that they were heterosexual, bisexual, or lesbian in response to the following item (P. Case, 1997), without implying current sexual activity:
Whether you are currently sexually active or not, what is your sexual identity or orientation? Please choose one answer: (a) heterosexual; (b) bisexual; (c) lesbian, gay, or homosexual; (d) none of the above; or (e) prefer not to answer.
The following WHI sexual behavior questions, placed at the end of the baseline self-administered questionnaire, had an item nonresponse rate of 3.2% (D. Bowen, 1997) and assess one dimension, sexual behavior, for two time frames (lifetime and after 45 years of age):
Question 125. Regardless of whether you are currently sexually active, which response best describes who you have had sex with over your adult lifetime? (1) Have never had sex. (2) Sex with a woman or with women. (3) Sex with a man or with men. (4) Sex with both men and women. (5) Prefer not to answer.
If answer 4 is given, then the next question is asked:
Question 125.1. Which response best describes who you have had sex with after 45 years of age? [Choose from options] 2 through 5 above.
NHANES III 16 included items for adult males, but not females, to 60 years of age on gender of lifetime sexual partners. NHANES 1999 included these sexual behavior questions for two recent time frames (last 12 months and last 30 days), as well as lifetime for both male and female adults to 60 years of age, and NHANES 2000 recently added a question on current self-identification (R. Kington, 2000).
Although these particular studies are not the only ones to measure sexual orientation among women, they have substantial experience to offer and show that the inclusion of sexual orientation items is feasible both in cross-sectional population-based studies and in longitudinal studies. These studies also demonstrate that researchers must specify or imply a relevant time frame when evaluating dimensions of sexual orientation. WPHS used the word “now” to assess current or recent behavior and self-identification. It is possible, although very unlikely, that “now” could be interpreted as instantaneously to completing the questionnaire, likely precluding sexual activity with anyone.
Virtually all WPHS respondents who self-identified as lesbian reported sexual activity with women only or with no one. Three-fourths of WPHS respondents who reported sexual activity only with women, however, self-identified as lesbian, with the remainder equally likely to identify as heterosexual or bisexual. These findings are consistent with results from Laumann et al 7 in their population-based study of 1,749 U.S. women 18–59 years of age and illustrate the desirability of including more than one dimension of sexual orientation in questionnaires. 6 Furthermore, given that 22% of WPHS respondents reported no sexual activity, even though almost all of them indicated an orientation identity, it becomes apparent that assessing only current or recent sexual behavior provides incomplete information to evaluate outcome variables other than sexually transmitted diseases or pregnancy risk.
The three definitions of lesbian and heterosexual in our study differ conceptually and yield somewhat different classifications of subjects for stratified analyses by sexual orientation. Other conceptual dimensions of orientation include attraction or desire 7; membership in lesbian social or political organizations 4; and degree of self-acknowledgment of sexual self-identification (“outness”) to relatives, friends, and co-workers. 4 Another approach 4 views each sexual orientation dimension on a continuum, as in the reports by Kinsey and colleagues, 17,18 contrary to the categorical questionnaire items reviewed above. Morris and Rothblum 4 have shown that several continuous dimensions of sexual orientation among a nonprobability sample of lesbians have only low or moderate correlations.
To compare lesbians with heterosexual women on health status and health behavior (excluding variables directly related to sexual behavior), we generally prefer the more inclusive definition of lesbian involving both behavior and self-identity. This definition includes women who are affected by one or both dimensions of same-sex sexual behavior and lesbian identity and does not imply that those who report sex only with women necessarily self-identify as lesbian, nor vice versa. We believe the behavior and identity dimensions define lesbians more strongly because they are overt statements or commitments to at least one other person (behavior) or to a community (identity) 19 that potentially incur more societal stigma and risk than do simple attraction or desire. We prefer not to include attraction or desire in our combined definition because few significant health or psychosocial outcomes are likely to correlate with this dimension. When investigating stigma or its effects, however, additional aspects of being lesbian may be important to assess, for example, “outness,” overtness, appearance, and social behavior.
We agree with Laumann et al, 7 ,pp.285–286 who state, “It makes more sense to ask about specific aspects of same-gender behavior, practice and feeling during specific periods of an individual’s life rather than a single yes-or-no question about whether a person is homosexual.” Indeed, most researchers agree that although most persons are raised as heterosexuals, a homosexual orientation can be recognized at any age from childhood on.
With the recent publication of the IOM report, 1 it is likely that more health research studies that focus on or include women, especially population-based surveys, will include items to allow analyses of health data stratified by sexual orientation. This research will confirm whether lesbians have a higher prevalence of some health risks and disorders, as well as of various protective factors. 5
Although researchers may assume that behavioral dimensions are easier to assess, Sanders and Reinisch 20 showed that a sample of college students held widely divergent opinions about the specific behaviors that defined having “had sex.” Many studies, for example, WPHS, NHS-2, WHI, and NHANES, are under pressure to limit the number of questions, so it is important to determine subjects’ interpretation of short phrases such as “had sex with” and “sexually active.” Respondent interpretation of items to assess dimensions of sexual orientation, as well as willingness to disclose a sexual orientation other than heterosexual, is best studied in a survey research cognitive laboratory. 21 The recent Scientific Workshop on Lesbian Health explicitly recommended that cognitive research on sexual orientation items in women’s health research be conducted in a timely manner.
We thank Dr. Suzanne Haynes for review of drafts of the manuscript and the referees for constructive comments.
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Keywords:© 2001 Lippincott Williams & Wilkins, Inc.
homosexuality/female,; homosexuality,; surveys,; sexual orientation,; physicians,; physicians/women.