Skip Navigation LinksSkip Navigation Links
Centers for Disease Control and Prevention
Safer Healthier People
Blue White
Blue White
bottom curve
CDC Home Search Health Topics A-Z spacer spacer
Blue curve MMWR spacer

Current Trends -- Number of Sex Partners and Potential Risk of Sex ual Exposure to Human Immunodeficiency Virus

Human immunodeficiency virus type 1 (HIV-1) and other sexually transmitted diseases (STDs) are spread from infected persons to their sex partners during unprotected sexual exposures (1). The Public Health Service estimates that between 945,000 and 1,410,000 Americans have been infected with HIV-1 (2), but the number of Americans at risk because of unprotected sexual exposures is unknown. Estimates of current levels of sexual activity are based in part on a survey of sexual behavior conducted 40 years ago (3).

The National Opinion Research Center (NORC) has been conducting an annual General Social Survey (GSS) on important social issues since 1972 (4). From February 14 to April 25, 1988, face-to-face interviews were conducted with a probability sample of adults (greater than or equal to18 years of age) residing in U.S. households. At the conclusion of the GSS interview, NORC interviewers asked respondents to complete and return in a sealed envelope a one-page self-administered questionnaire that included the following questions:

How many sex partners have you had in the last 12 months? Was one of the partners your husband or wife or regular sex partner? If you had other partners, please indicate all categories that apply to them-- close personal friend; neighbor, co-worker, or long-term acquaintance; casual date or pick-up; person you paid or (who) paid you for sex; other.

Have your sex partners in the last 12 months been exclusively male, both male and female, or exclusively female?

The GSS response rate in 1988 was 77.3%; 93.9% of the 1481 respondents answered the question about number of sex partners in the past 12 months (Table 1). Overall, 21.5% said they had no sex partner in the past 12 months, 59.6% said one, 10.6% said two to four, 2.2% said five or more, and 6.1% did not answer the question. Six percent of the 638 men and 1.2% of the 843 women indicated that at least one of their sex partners in the past 12 months was a "casual date or pick-up." Four (0.6%) men and no women reported that at least one of their partners was a "person you paid or (who) paid you for sex."

Of the 504 men who reported having one or more sex partners within the past 12 months,* 14 (2.8%) reported their partners were exclusively male, two (0.4%) indicated their partners included males and females, 460 (91.3%) indicated their partners were exclusively female, and 28 (5.6%) did not answer this question. Of the 14 men who said they had sexual intercourse with male partners exclusively, 10 reported one partner in the past 12 months, two reported three partners, one reported four partners, and one reported between 21 and 100 partners. Six of the 16 men with homosexual exposures said they were married at the time of interview, eight had never married, and two had been married previously. Of the 567 women who reported having one or more partners within the past 12 months, one (0.2%) reported her partners were exclusively female, 541 (95.4%) reported their partners were exclusively male, and 25 (4.4%) did not answer this question. Reported by: RT Michael, PhD, EO Laumann, PhD, JH Gagnon, PhD, TW Smith, PhD, National Opinion Research Center, Univ of Chicago, Illinois. AIDS Program, Center for Infectious Diseases, CDC.

Editorial Note

Editorial Note: Many epidemiologic models of the sexual transmission of HIV-1 (5) and other STDs (6) require estimates of the average rate of acquiring new sex partners per unit of time. These estimates can be obtained from reliable data on the numbers of sex partners reported by men and women classified by age and marital status. The distributions reported in the GSS suggest that the vast majority of the U.S. population has no or only one sex partner within a year; thus, most Americans appear to be at relatively low risk of infection with HIV-1 and other STDs from sexual exposures.

However, a sizeable percentage of young, never-married men report more than 10 partners in the past 12 months: 4.6% of those aged 18-29 years and 2.9% of those aged 30-44 years. When these percentages are applied to the total number of such men in the United States (7), over 700,000 single men 18-29 years and over 100,000 single men 30-44 years may have 10 or more partners per year and hence appear to be at considerable risk of sexual exposure to HIV-1 and other STDs.

The distribution of partners reported in the GSS is similar to another survey of 713 adults aged 18-64 years conducted in November 1986 in the United Kingdom (8). In that survey, 20% of 481 men and 25% of 232 women reported no partners of the opposite sex in the prior 12 months, 66% of men and 65% of women reported one partner, 9% of men and 3% of women reported two or more partners, and 5% of men and 7% of women refused to answer or were not asked the question. Similarly, a U.S. telephone survey of 2095 adults conducted by the Los Angeles Times in July 1987 yielded estimates of 15% with no sex partners in the last year, 70% with one partner, 8% with two to four partners, 3% with five or more partners, and 4% refused to answer or were "not sure."

While the response rate in the GSS varies by a few percentage points from one year to another, the 1988 rate of 77.3% is well within the usual range. Furthermore, GSS data compare closely with decennial census and current population survey data on the demographic and economic characteristics of the U.S. population (9). Almost half (47%) the 1481 respondents in the 1988 GSS were telephoned after the survey to verify that they had participated, and these telephone call-backs provide additional confidence in the quality of the GSS data. Finally, those who did not respond to the self-administered sex-partner questionnaire (6.1%) did not appear to be different in their demographic characteristics (sex, age, race, or marital status) from those who responded; however, nonrespondents to the sex-partner supplement were slightly less well educated.

Nevertheless, the GSS sample size was small, and respondents may have been reluctant to answer sensitive questions about sexual activities with the same degree of candor with which they answer less sensitive questions. Further studies with larger samples are under way to assess the validity of responses to sensitive questions about sexual activities and to obtain better estimates of the risk of sexual exposure to HIV-1 and other STDs in the United States.


  1. Curran JW, Morgan WM, Hardy AM, Jaffe HW, Darrow WW, Dowdle WR. The epidemiology of AIDS: current status and future prospects. Science 1985;229:1352-7.

  2. CDC. Human immunodeficiency virus infection in the United States: a review of current knowledge. MMWR 1987;(suppl S-6):40.

  3. Kinsey AC, Pomeroy WB, Martin CE. Sexual behavior in the human male. Philadelphia: WB Saunders, 1948.

  4. Davis JA, Smith TW. General Social Surveys, 1972-1987: cumulative codebook. Chicago: National Opinion Research Center, 1987.

  5. May RM, Anderson RM. Transmission dynamics of HIV infection. Nature 1987;326:137-42.

  6. Hethcote HW, Yorke JA. Gonorrhea transmission dynamics and control. Berlin: Springer- Verlag, 1984. (Levin S, ed. Lecture notes in biomathematics; vol 56).

  7. Bureau of the Census. Statistical abstract of the United States: 1988. Washington, DC: US Department of Commerce, Bureau of the Census, 1987:40.

  8. British Market Research Bureau Limited. AIDS advertising campaign: report on four surveys during the first year of advertising, 1986-87. London: Department of Health and Social Security and the Welsh Office, Her Majesty's Stationery Office, 1987.

  9. Smith TW, Fujimoto R. Annotated bibliography of papers using the General Social Surveys. 6th ed. Chicago: National Opinion Research Center, 1986. *The 1988 GSS data set is available at a cost of $100 from the Roper Center for Public Opinion Research, P.O. Box 440, Storrs, CT 06268; telephone: (203) 486-4440. In the public-use tape, nine respondents are coded as having "one or more partners"; seven were recoded for this analysis to have one partner. It appears that all these persons misunderstood and did not count their spouses as sex partners although they listed their spouses as one. The other two were men and were recoded here to have two partners because one listed a spouse and an acquaintance while the other listed a spouse and a friend.

Disclaimer   All MMWR HTML documents published before January 1993 are electronic conversions from ASCII text into HTML. This conversion may have resulted in character translation or format errors in the HTML version. Users should not rely on this HTML document, but are referred to the original MMWR paper copy for the official text, figures, and tables. An original paper copy of this issue can be obtained from the Superintendent of Documents, U.S. Government Printing Office (GPO), Washington, DC 20402-9371; telephone: (202) 512-1800. Contact GPO for current prices.

**Questions or messages regarding errors in formatting should be addressed to

Page converted: 08/05/98


Safer, Healthier People

Morbidity and Mortality Weekly Report
Centers for Disease Control and Prevention
1600 Clifton Rd, MailStop E-90, Atlanta, GA 30333, U.S.A


Department of Health
and Human Services

This page last reviewed 5/2/01