Component Description
The ACASI section on sexual behavior (SXQ) provides information on lifetime and current sexual behavior for both men and women. Major items in this section include age at first sexual intercourse, number of sexual partners, sexual orientation, circumcision status (men) and history of sexually transmitted diseases.
Eligible Sample
Sample persons aged 14-59 years were eligible. Several questions in this section are age and gender specific. Mentally impaired individuals or participants who were unable to understand English or Spanish were not asked these questions. Only data from participants aged 20-59 years are included in this release. Special use data files for participants 14-19 years are available through the NCHS Research Data Center.
Interview Setting and Mode of Administration
The sexual behavior questionnaire was administered during the physical examination, at the examination center in a private room, using the Audio Computer Assisted Self Interview (ACASI) system for study participants 14 and older.
The ACASI was conducted in either English or Spanish. The ACASI enables respondents both to hear questions through earphones and read questions on the computer screen. Respondents move at their own speed and touch the screen to indicate their response. No proxy respondents or translators were used in situations when the respondents could not self-report.
Quality Assurance & Quality Control
For details on the QA/QC process for this component, please refer to the MEC Interview Manual on the NHANES website.
Data Processing and Editing
Responses to SXD031 (age at first sexual intercourse) that were 9 years or less were grouped and coded as “9 years or younger.”
Responses to SXD171 (# of female partners) that were 2000 or more partners were grouped and coded as “2000 or more” partners.
Analytic Notes
Questions have changed from the NHANES Sexual Behavior 2003-2004 Public Data Release. Many of these changes were rewording of the questions to make them more specific (see table 1), as well as new questions added (see table 2). Analysts should take this into account and make sure they are familiar with all the questions before trying to merge datasets.
Table 1. Comparison of 2003-2004 questions with 2005-2006.*
| 2003-2004 Question Variable |
2003-2004 Question |
2005-2006 Question Variable |
2005-2006 Question |
| SXQ.020 |
The next set of questions is about your sexual behavior. By sex, we mean vaginal, oral, or anal sex. Please remember that your answers are strictly confidential.
Have you ever had sex? (B) |
SXQ.021 |
The next set of questions is about your sexual behavior. By sex, we mean vaginal, anal, or oral sex. Please remember that your answers are strictly confidential.
Have you ever had vaginal, anal, or oral sex? (B) |
| SXQ.030 |
How old were you when you had sex for the first time? (B)
|
SXQ.031 |
When you first had vaginal, anal, or oral sex, how old were you? (B) |
| SXQ.100 |
In your lifetime, with how many men have you had sex? (F)
|
SXQ.101 |
In your lifetime, with how many males have you had vaginal, anal, or oral sex? (F) |
| SXQ.120 |
In the past 12 months, with how many men have you had sex? (F) |
SXQ.450 |
In the past 12 months, with how many males have you had vaginal, anal, or oral sex? (F) |
| SXQ.130 |
In your lifetime, with how many women have you had sex? (F) |
SXQ.130 |
In your lifetime, with how many females have you had sex? (F) |
| SXQ.150 |
In the past 12 months, with how many women have you had sex? (F) |
SXQ.490 |
In the past 12 months, with how many females have you had sex? (F) |
| SXQ.170 |
In your lifetime, with how many women have you had sex? (M) |
SXQ.171 |
In your lifetime, with how many females have you had vaginal, anal, or oral sex? (M) |
| SXQ.190 |
In the past 12 months, with how many women have you had sex? (M) |
SXQ.510 |
In the past 12 months, with how many females have you had vaginal, anal, or oral sex? (M) |
| SXQ.200 |
In your lifetime, with how many men have you had sex? (M) |
SXQ.410 |
In your lifetime, with how many males have you had anal or oral sex? (M) |
| SXQ.220 |
In the past 12 months, with how many men have you had sex? (M) |
SXQ.550 |
In the past 12 months, with how many males have you had anal or oral sex? (M) |
| SXQ.250 |
In the past 30 days, how many times have you had sex without using a condom? (B) |
SXQ.251 |
In the past 12 months, about how often have you had vaginal or anal sex without using a condom? (B) |
*These are the variable numbers used in the collection instrument, actual variable numbers in the dataset may be slightly different.
Table 2. New Questions in 2005-2006
| Variable |
Question |
|
SXQ.350
SXQ.470
|
With how many of these males have you had only oral sex? (F) |
SXQ.400
SXQ.530 |
With how many of these females have you had only oral sex? (M) |
SXQ.430
SXQ.570 |
With how many of these males have you had only oral sex? (M) |
| SXQ.610 |
In the past 12 months, about how many times have you had vaginal or anal sex? (B) |
| SXQ.590 |
Of the persons you had sex with in the past 12 months, how many were five or more years older than you? (B) |
| SXQ.600 |
Of the persons you had sex with in the past 12 months, how many were five or more years younger than you? (B) |
(B) = asked to both male and female respondents
(M) = only asked to males respondents
(F) = only asked to female respondents
Compared to past NHANES cycles, the prevalence has gone up for respondents answering “No” to ever having sex, including respondents who were pregnant at exam, gave a history of pregnancy or self-reported being married, divorced, widowed, separated, or living with a partner. Analysts are advised to recode SXQ021 based on pregnancy status, ever been pregnant and marital status. Data will be missing for most of the variables in the sexual behavior section for these respondents since an answer of “No” to SXQ021 skips the respondent out of the questionnaire, with an exception of one other question for females and 2 other questions for males.
Although this issue is more pronounced in the 2005-2006 data release, this was also an issue in previous releases. If analysts are planning to combine data with previous cycles they may want to consider the same type of recode for SXQ020.
Pregnancy Status (RIDEXPRG): If pregnancy status is coded as “1”, or ‘Yes, positive lab pregnancy test or self-reported pregnant at exam’, then analyst should recode SXQ021 (Have you ever had vaginal, anal, or oral sex?) to equal “1” or ‘Yes’. There were approximately 13 women who reported “2” or ‘No’ to SXQ021 who were pregnant at exam. Below is a table illustrating the prevalence of women for the 2005-2006 data reporting “no” to SXQ021 based on pregnancy status.
Table 3. Adult (20-59) female prevalence estimates for NEVER had vaginal, anal, or oral sex (SXQ021 = 2) and pregnancy status (RIDEXPRG), for complete and partial exams of the sexual behavior questionnaire(SXAISC=1 or SXAISC=2), NHANES 2005-2006
| Pregnancy Status |
Sample Size |
Percent* never had sex |
95% CI |
| Total females with complete and partial SXQ questionnaire |
1568 |
4.9 |
3.9-6.1 |
| Pregnant at exam |
305 |
6.1 |
2.5-14.4 |
| Not pregnant at exam |
1234 |
4.8 |
3.9-6.0 |
| Cannot ascertain |
29 |
3.9 |
0.6-21.8 |
| Missing |
0 |
. |
. |
*Prevalence estimates are weighted
Pregnancy History (RHQ131): If RHQ131 (Have you ever been pregnant? Please include current pregnancy, live births, miscarriages, stillbirths, tubal pregnancies and abortions.) is equal to “1”, or ‘Yes’, then analyst are urged to recode SXQ021 to “1” or ‘Yes’. Below is a table illustrating the prevalence of women for the 2005-2006 data reporting “no” to SXQ021 based on pregnancy history.
Table 4. Adult (20-59) female prevalence estimates for NEVER had vaginal, anal, or oral sex (SXQ021 = 2) and EVER been pregnant (RHQ131), for complete and partial exams of the sexual behavior questionnaire (SXAISC=1 or SXAISC=2), NHANES 2005-2006
| Ever been pregnant |
Sample Size |
Percent* never had sex |
95% CI |
| Total females with complete and partial SXQ questionnaire |
1568 |
4.9 |
3.9-6.1 |
| Yes |
1322 |
2.8 |
1.8-4.2 |
| No |
244 |
13.4 |
9.2-19.1 |
| Missing |
2 |
0.0 |
. |
*Prevalence estimates are weighted
Marital Status (DMDMARTL): Analyst are urged to recode SXQ021 to “1” if the marital status =:
“1” (Married)
“2” (Widowed)
“3” (Divorced)
“4” (Separated)
“6” (Living with Partner)
Below is a table illustrating the prevalence by gender for the 2005-2006 data reporting “no” to SXQ021 based on marital status.
Table 5. Adult (20-59) prevalence estimates for NEVER had vaginal, anal, or oral sex (SXQ021 = 2) by gender, and marital status, for complete and partial exams of the sexual behavior questionnaire(SXAISC=1 or SXAISC=2), NHANES 2005-2006
| Marital Status |
Sample Size |
Percent* never had sex |
95 % CI |
| Total males and females with complete or partial SXQ questionnaire |
2931 |
8.3 |
6.9-10.0 |
| M/W/D/S/LwP** |
2327 |
7.0 |
5.8-8.4 |
| Never Married |
602 |
14.3 |
10.8-18.8 |
| Missing |
2 |
0.0 |
. |
| Total males with complete or partial SXQ questionnaire |
1363 |
11.8 |
9.6-14.5 |
| M/W/D/S/LwP** |
1069 |
11.4 |
9.4-13.9 |
| Never Married |
293 |
13.4 |
9.3-18.8 |
| Missing |
1 |
0.0 |
. |
| Total females with complete or partial SXQ questionnaire |
1568 |
4.9 |
3.9-6.1 |
| M/W/D/S/LwP** |
1258 |
2.7 |
1.9-3.8 |
| Never Married |
309 |
15.4 |
11.4-20.3 |
| Missing |
1 |
0.0 |
. |
*Prevalence estimates are weighted
** Married/Widowed/Divorced/Separated/Living with Partner
Users are cautioned about the use of SXQ292 and SXQ294 in analyses, especially in analyses that classify respondents by their responses to these questions to describe or compare subgroup characteristics. The sample size for the non-heterosexual subgroups is limited and do not meet the minimum sample size requirements for statistical reliability as noted in the NHANES analytic guidelines1. Even after combining multiple years of data, which is often recommended to estimate rarer conditions within a subgroup, the non-heterosexual subgroups do not meet the minimum sample size. Additionally, there is a high rate of not selecting a specific answer to the questions. That is, selecting ‘don’t know’, ‘refused’, ‘not sure’ or ‘something else’ as a response. This issue has been examined at length at the NCHS Questionnaire Design Research Laboratory (QDRL) recently. Individuals select these answers for a variety of reasons that are well summarized in the report Design, Development and Testing of the NHIS Sexual Identity Question2, specifically in Table 2. For example, respondents from the LGBT community select “something else’ when they use a different sexual identity label than those presented in the response options. However, those who aren’t part of the LGBT community select this answer because they are not familiar with what the response options mean.
Please refer to the Analytic Guidelines for further details on the use of sample weights and other analytic issues on the NHANES website. The Analytic Guidelines are available on the NHANES website.