1. Same-sex sexual behavior and sexual risk behaviors among in-school youth: Findings from a large population-based sample
Preeti Pathela1 and Julia A. Schillinger1,2
1 New York City Department of Health and Mental Hygiene, New York
2 Centers for Disease Control and Prevention, Division of Sexually Transmitted Disease Prevention, Atlanta
The findings and conclusions in this presentation are those of the authors and do not necessarily represent the views of the CDC/ATSDR

2. Background Burden of disease
Sexually transmitted infections (STI) disproportionately affect adolescents
By 2004, ~40,000 cumulative cases of AIDS in the U.S. were among persons aged years
New HIV diagnoses among year olds ↑ by 20% from 2004 to 2005
The majority of infected male and female adolescents acquire HIV through sex with males
A number of bacterial sexually transmitted infections affect adolescents disproportionately and there is a growing concern about HIV/AIDS among U.S. adolescents and young adults
The CDC reported approx. 40,000 cumulative cases of AIDS among persons aged 13 to 24 years through Because the average duration from HIV infection to the development of AIDS is 10 years, most young adults with AIDS were likely infected with HIV as adolescents.
The number of new adolescent cases has been on the rise; from 2004 to 2005, new HIV diagnoses among persons aged years increased by 20%.
Surveillance data on transmission category suggest that the majority of infected male and female adolescents acquire HIV through sex with males.
33 states with confidential name-based HIV infection reporting:
New HIV 2004: 1,012
2005: 1,213

3. Background The adolescent period
Adolescence is a period of sexual experimentation
Challenges for adolescents with same-sex partners include:
rejection
isolation
verbal abuse
physical violence
poor access to confidential health care
Studies document higher rates of sexual risk behaviors among youth who report same-sex partners
Adolescence is the formative period during which sexual experimentation and identity development take place.
In addition to the usual social and personal challenges that accompany adolescence, youth exploring same sex or bisexual sexual experiences may have additional stress resulting from higher levels of rejection, isolation, verbal abuse, physical violence, and poor access to confidential health care.
Several studies have documented riskier sexual behaviors among youth with same sex partners that increase their risk for STI, including HIV.

4. Background Limitations of previous research
Convenience samples
Survey self-identified gay, lesbian, and bisexual youth
Population-based survey data
Combine male and female respondents
Combine respondents who have:
exclusively same-sex partners
both male and female sex partners
There are limitations to research done to date. Many studies on sexual risk behaviors and related outcomes have relied on convenience samples, and furthermore those studies have categorized respondents based on sexual identity, not sex of partners. Population-based studies have employed varying measures to classify respondents, such as the sex of their partners regardless of whether they have had sexual intercourse. Some of these studies haven’t included gender comparisons, or have combined respondents with bisexual and exclusively same-sex behavior. However persons who are bisexual by self-identification or behavior have been found to differ in sexual risk and outcomes from persons who are exclusively homosexual and should probably not be grouped

5. Objectives of this analysis
Use population-level data:
To describe adolescents’ demographics and sexual behaviors, based on sex of partners
Focus on adolescents who have had sexual experiences with both males and females
To compare self-reported sexual identities for groups reporting sexual activity with members of the same, opposite, and both sexes
Our objectives, using population level data, were:
To describe adolescents’ demographics and sexual behaviors, based on sex of partners and particularly for an understudied group: adolescents who have had sexual experiences with both males and females.
And to characterize sexual identity and sexual behavior, as a means of identifying youth at elevated risk because they are less likely to seek or be identified for prevention information.

6. Methods The NYC Youth Risk Behavior Survey (YRBS)
NYC’s sample within the CDC’s National Youth Risk Behavior Surveillance System
assesses trends in health risk behaviors among high school students via in-school, self-administered, anonymous surveys
A two-stage cluster sample design accounts for high school, then classroom, and produces a representative sample of NYC public high school students
2005 NYC YRBS:
87 / 91 selected schools participated
8,187 / 11,710 students participated
Overall response rate: 68%
We included a sample of high school students who completed the 2005 New York City Youth Risk Behavior Survey (YRBS), which is the city’s sample within the CDC’s National Youth Risk Behavior Surveillance System that assesses trends in health risk behaviors via in-school surveys.
The NYC YRBS is the largest of 15 state or local youth risk behavior surveys that were conducted in 2005.
A two-stage cluster sample design that accounts for high school and classroom produces a representative sample.
In 2005, 11,710 students in 91 schools throughout the 5 boroughs of NYC had an equal probability of selection for survey. 87 schools participated, yielding a sample of 8,187 students, and an overall response rate of 68%.
School probability of selection proportional to enrollment size
2005 MA YRBS: 68%, Alaska YRBS: 60% (CDC reqs >60% to be representative of state/jurisdiction), Indiana YRBS: 68%, Nevada YRBS: 60%

7. Methods Pertinent NYC YRBS questions
Sexual experience
“Have you ever had sexual intercourse?”
Yes/no
Sex of partner(s)
“During your life, with whom have you had sexual contact?”
Never had sexual contact, females, males, females & males
Sexual identity
“Which of the following best describes you?”
Heterosexual (straight), gay or lesbian, bisexual, not sure
The NYC YRBS included a question asking whether the adolescent had ever had sexual intercourse.
Respondents were asked about the sex of persons with whom they had had sexual contact. Response categories were: “I have never had sexual contact,” “Females,” “Males,” and “Females and males.” Neither “intercourse” nor “sexual contact” was specifically defined in these questions.
The 2005 NYC YRBS included a question to measure sexual identity: “Which of the following best describes you?” with response categories of “Heterosexual (straight),” “Gay or lesbian,” “Bisexual,” and “Not sure.”

8. Methods Pertinent NYC YRBS questions
Sexual behaviors
Age at first intercourse
Number of lifetime sex partners
Number of sex partners in the last 3 months
Condom use at last intercourse
Alcohol or drug use at last intercourse
History of forced sex (ever)
Dating violence during last year
Other questions included age at first intercourse, number of lifetime sex partners, number of partners in the last 3 months, whether a condom had been used by the respondent or his or her partner at last intercourse, whether alcohol or drugs had been used before last intercourse, whether there was a history of forced sex, and whether there was incidence of dating violence during the last year.

9. Methods Analysis Study population:
Respondents who reported ever having intercourse & the sex of persons with whom they had sexual contact
Behavior groups:
Contact with same-sex, opposite-sex, and partners of both sexes
For respondents reporting ever having had intercourse, behavior group assignment was based on the sex of persons with whom they reported contact. 3 behavior groups of males and females were constructed: those with only same-sex partners, only opposite-sex partners, and partners of both sexes.

10. Methods Analysis (cont.)
Data weighted to adjust for school and student nonresponse (weighted sample N=116,134)
Prevalence estimates for demographic and risk characteristics, by behavior group
Distribution of sexual identities among behavior groups
SUDAAN software used to obtain appropriate SEs for point estimates
Data were weighted to adjust for school and student nonresponse
Demographic and selected risk characteristics were described for the behavior subgroups. Separately, the distribution of self-reported sexual identities of respondents in each subgroup was examined.

11. Results Survey respondents
8118 students
49% male
76% aged years
Age distributions for males & females similar
57% of males reported having had intercourse
46% of females reported having had intercourse
Of 8118 students for whom sex was known, 49% were male. Most respondents were years old. The age distributions for males and females were similar. Overall, 57% of males and 46% of females answering the question on sexual intercourse reported that they had had sex.
Unweighted data

12. Results Sex of partners
Virtually all sexually active students reported the sex of persons with whom they had sexual contact and were included in this analysis. Among males: 94% had opposite sex, 3% had same-sex, and 3% had both sex partners. Among females: 88% had opposite sex, 3% had only same sex, and 9% had both-sex partners. So, males and females were equally likely to report same-sex only behavior but females were three times more likely than males to report bisexual behavior.
Males and females were equally likely to report same-sex only behavior but females were 3x more likely than males to report bisexual behavior (p<.001)
Unweighted data

13. Results Percent males reporting opposite, same, and both-sex partners, by race & ethnicity
A high proportion of males in each of 3 racial/ethnic groups (non-Hispanic White, non-Hispanic Black, Hispanic) reported sexual contact only with the opposite sex, however non-Hispanic White males were more likely than other males to report partners of both sexes

14. Results Male sexual behaviors
Sex of partner(s) reported
Opposite sex
Same sex
Both sex
N=57,825
N=1,481
N=2,289 %
Age at 1st sex
<=13
14-15
>=16
53.4*
36.4
10.2
27.6*
64.0*
8.4
77.1
14.9
8.0
No. lifetime partners 1
2-5
>=6
23.1*
49.2*
27.7*
33.2*
50.6*
16.2*
7.4
25.9
66.7
No. ptrs last 3 months
>=2
53.9*
46.1*
72.2*
27.8*
17.4
82.6
Statistically significant differences in weighted prevalence estimates (at the .05 alpha level) between persons with partners of both sexes and other groups are denoted by asterisks.
Males with male and female partners were more likely than those with opposite sex and with only same sex partners to report an earlier age at first sex, with an average age at sexual debut of 13 years compared to 15 years for the other 2 groups.
Males with male and female partners were much more likely to report a greater number of both lifetime and recent sex partners; for males reporting having had sex within the past 3 months, 83% of respondents with both-sex versus 46% with opposite-sex (p=0.0003) and 28% with only same-sex partners (p<0.0001) reported sex with 2 or more partners.
* Significant difference compared to group with male & female partners

15. Results Male sexual behaviors
Sex of partner(s) reported
Opposite sex
Same sex
Both sex
Reported:
N=57,825
N=1,481
N=2,289 %
Alcohol/drugs at last sex
17.0*
1.8*
48.1
Condom use at last sex
78.7*
77.0*
28.0
Partner violence
(past year)
12.1*
7.4*
32.5
Forced sex (ever)
6.6*
4.2*
28.1
Males with both male and female partners were much more likely than the other 2 male groups to report the use of alcohol and/or drugs with the last sexual encounter.
A notably small proportion of males with both sex partners (28%) reported using a condom during the last sexual encounter, compared to 77-79% of other groups (p< for condom use, both-sex vs. same-sex males).
Males with both sex partners were significantly more likely than the other 2 groups to report being a victim of intimate partner violence in the previous year and a victim of forced sex.
* Significant difference compared to group with male & female partners

16. Results Percent females reporting opposite, same, and both-sex partners, by race & ethnicity
Similar to males, non-Hispanic White females (18%) were more likely than non-Hispanic Black (7%) and Hispanic females (8%) to report both male and females partners

17. Results Female sexual behaviors
Sex of partner(s) reported
Opposite sex
Same sex
Both sex
N=47,954
N=1,683
N=4,901 %
Age at 1st sex
<=13
14-15
>=16
24.4*
53.1
22.5*
58.5
35.8
5.8
42.6
51.3
6.2
No. lifetime partners 1
2-5
>=6
41.0*
47.7
11.3*
57.7*
24.7*
17.6
13.6
55.4
31.0
No. ptrs in last 3 months
>=2
81.3*
18.7*
47.4
52.6
64.1
35.9
Females with both sex and only same-sex partners were largely similar to each other with regard to risk behaviors.
43% of females with both sex and 59% of females with only same-sex partners reported first sex before age 14 years, compared to 24% of those with opposite-sex partners (p=0.03).
Females with male and female partners were more likely than those with opposite-sex partners but equally likely as those with only same-sex partners to report 6 or more lifetime partners and 2 or more partners in the past 3 months.
* Significant difference compared to group with male & female partners

18. Results Female sexual behaviors
Sex of partner(s) reported
Opposite sex
Same sex
Both sex
Reported:
N=47,954
N=1,683
N=4,901 %
Alcohol/drugs
at last sex
10.8*
14.3
25.9
Condom use
68.8
63.9
55.1
Partner violence (past year)
15.2*
9.3*
34.6
Forced sex
(ever)
16.7
2.6*
27.5
Females with male and female partners were also more likely than those with opposite-sex, but equally likely as those with only same-sex partners to report the use of alcohol and/or drugs with the last sexual encounter.
There were no differences between groups regarding condom use.
Those with male and female partners were more likely than the other female groups to report sexual violence; similar to males with both-sex partners, approximately one-third reported intimate partner violence. Also similar to what was seen for males with both-sex partners, 28% of females with both-sex partners reported forced sex, however the difference in prevalence of forced sex between females with both-sex and opposite sex partners (17%) was not significantly different.
* Significant difference compared to group with male & female partners

19. Results Male sexual identity and behavior
Weighted % in each group
All males
Sex of partner(s) reported
Opposite sex
Same sex
Both sex
Heterosexual
(Straight) 94 98 57 15
Gay 1 38
Bisexual 3 4 71
Unsure 12
Now I’ll switch gears to talk about sexual identity findings. Along the left side are the identity categories, and across the top are the groups of males according to sex of partners. Groups with discordant identity and behavior are circled.
Among males, the greatest degree of discordance (57%) occurred among those who reported exclusively same-sex behavior but a heterosexual identity. Of males with partners of both sexes, 15% reported a heterosexual identity.
= discordant group with respect to identity & behavior

20. Results Female sexual identity and behavior
Weighted % in each group
All females
Sex of partner(s) reported
Opposite sex
Same sex
Both sex
Heterosexual
(Straight) 87 94 79 26
Gay/lesbian 1 7 4
Bisexual 8 3 13 64
Unsure 2 6
Discordance findings were more striking among females. Among females with only same sex partners, a combined 92% reported a sexual identity other than gay/lesbian; 79% reported a heterosexual identity, and an additional 13% reported a bisexual identity. Of females with male and female partners, 26% considered themselves heterosexual.
Future analyses of these data will explore identity-behavior discordance as a potential predictor of some of the sexual risk behaviors I’ve just presented.
= discordant group with respect to identity & behavior

21. Limitations
Homeless youth and youth in alternative schools not surveyed
Missing populations that may have ↑ proportion of persons with same-sex partners
Self-reported behaviors subject to social desirability bias
No definition or referent period for sexual contact
“Sexual intercourse” not defined
Sample size did not allow for examination of risk behaviors by race and ethnicity
There are some limitations to our analysis.
The YRBS misses homeless youth and youth in alternative schools. However, it remains one of the strongest methods for tracking health and risk behaviors among the majority of U.S. adolescents.
The YRBS relied on self-report of many sensitive and stigmatized behaviors and experiences, but respondents social desirability bias was likely minimized by the self-administered, anonymous survey procedures. (Additionally, high rates of sexual abuse and multiple sex partners reported by a substantial proportion of our sample suggest that respondents were probably honest in their answers).
Sexual contact was not defined in terms of vaginal/anal/oral sex and no referent period was defined for the question. As a study of adolescents, it could be assumed that reported behaviors were recent as the time to have accumulated sexual experiences was relatively short. “Sexual intercourse” was not defined, increasing the possibility that oral sex was not included in the perception of sexual activity, and thereby underestimating respondents who could be included in the analysis.
Last, although we report on a larger number of in-school adolescents than other published research, our sample size did not allow for testing for possible variation in behaviors by race and ethnicity.

22. Conclusions & Implications
Almost 1 in 5 NYC high school youth report same-sex partners
Prevention messages must be appropriate for a broad audience that includes persons with same-sex attraction/behavior
Youth with same-sex partners report earlier age at 1st sex, and the subset with both male & female partners report a higher prevalence of risk behaviors
Sexual health education should include the need to inquire about partners’ sex of partners
In NYC, our estimate of same-sex behavior is higher than what has been reported in other population-based studies of adolescents. Prevention messages must be appropriate for a broad audience that includes youth with same-sex attraction or behavior; sexual health education programs that emphasize unintended pregnancy prevention and abstinence until marriage are not equally relevant for youth with opposite-sex and same-sex partners.
Youth with same-sex partners report an earlier sexual debut, and the subset of adolescents who reported both male and female partners exhibit a higher prevalence of several behaviors that influence STI transmission, such as a greater number of sex partners, use of alcohol and/or drugs with sex, experience with intimate partner violence and sexual abuse, and a lower prevalence of recent condom use for males.
Given these risks, sexual health education should include the need for sexually active youth to inquire about the sex of their partners’ partners.

23. Conclusions & Implications
Many students reported intimate partner violence & sexual abuse
health care providers should ask teenagers about whether they have been victimized
providers should be familiar with available & appropriate referrals
Given the discordance between sexual behavior and sexual identity, it is not appropriate to target groups for prevention based on identity
Providers of adolescent health care should take thorough sexual histories that ascertain information on sex of partners and specific sexual acts
Many respondents with male and female partners were the victims of sexual violence. (Approximately one-third experienced partner violence, and over one-quarter reported sexual abuse).
Appropriate intervention to reduce the likelihood of further victimization and psychological and substance abuse problems in adulthood is more likely if pediatricians and school health providers ask about sexual violence when speaking with teenagers. And importantly, providers should know what to do when they find out about sexual violence in terms of available and appropriate referrals, recognizing that those may be very different from what is appropriate for adults.
Finally, given the discordance between sexual behavior and sexual identity, it is not appropriate to target groups for prevention based on identity alone, and providers of adolescent care should take thorough sexual histories that ascertain information on sex of partners as well as specific sexual acts.

24. Acknowledgements NYC DOHMH Division of Epidemiology
The NYC schools and students who provide valuable information by completing the YRBS