In our article on the sexual orientation, sexual behavior, and sexual risk exposure of adolescents in the U.S. National Longitudinal Lesbian Family Study (NLLFS) (Gartrell, Bos, & Goldberg, 2011), we compared the sexual behavior of the 17-year-old adolescents in our sample with same-age adolescents in a national probability sample—the 2002 U.S. National Survey of Family Growth (NSFG Cycle 6) (U.S. Department of Health and Human Services, 2005, 2006). The NSFG data were weighted to ensure that the sample was similar to the United States population in terms of gender, age, and race/ethnicity. The NLLFS and NSFG participants entered their responses to the questions directly into computers, in private.

After obtaining the permission of the National Center for Health Statistics, the 17-year-old adolescents in the NSFG Cycle 6 were selected, consisting of 235 girls and 199 boys. For these 17-year-old NSFG adolescents, weighted frequencies and means were computed for the following variables: (1) heterosexual contact, same-sex contact, and the prevalence of sexually transmitted infections (separately for adolescent girls and boys); (2) contraception and pregnancy (only for adolescent girls); and (3) impregnation (only for adolescent boys). Comparing the above-mentioned variables in the NLLFS and NSFG Cycle 6 samples revealed that the NLLFS adolescent girls and boys were significantly older than their gender-matched peers in the NSFG were at the time of their first heterosexual contact. In addition, the NLLFS adolescent girls were significantly more likely to have had sexual contact with other girls and, among girls who were heterosexually active, the NLLFS girls were significantly more likely to have used emergency contraception and less likely to have used other forms of contraception than NSFG girls. The NLLFS adolescent boys were significantly less likely to have been heterosexually active by the age of 17 than the NSFG Cycle 6 boys, but no more likely to have engaged in same-sex sexual contact (see Table 1).

Table 1 Sexual behavior: NLLFS versus NSFG 17-year-old adolescents of the 6th and 7th Cycle
Full size table

In March 2011, the results of the NSFG Cycle 7 data collection (2006–2008) were released by the National Center for Health Statistics, with a public report that twice as many women reported same-sex contact in their lifetimes as men (Chandra, Mosher, Copen, & Sionean, 2011). Because the Cycle 7 data collection corresponded more closely with the time that we were collecting the data on the NLLFS adolescents (2006-2009), we thought it would be interesting to repeat the comparative analyses we conducted for our article, using the 2006-2008 NSFG ACASI data with permission of the National Center for Health Statistics (G. Martinez, personal communication, August 1, 2011; U.S. Department of Health and Human Services, 2010, 2011).

Using the same selection criteria and statistical analyses that we used for our article, the 17-year-old adolescents in the NSFG Cycle 7 were selected, consisting of 237 girls and 267 boys. Comparative analyses revealed that the findings for the 17-year-old NLLFS and NSFG boys were, with one exception, the same using the 2002 NSFG Cycle 6 as the 2006-2008 Cycle 7 data. The NLLFS boys were older than the NSFG boys at first heterosexual contact was significant when the comparison was based on the 6th but not the 7th cycle data. For the 17-year-old girls, comparisons between the NLLFS and NSFG 2006–2008 data revealed no significant differences in same-sex behavior or the use of emergency contraception, whereas there were significant differences in these measures when using the 2002 data (see Table 1).

These findings suggest that the Cycle 7 NSFG data on adolescent sexual behavior more closely matches that of the NLLFS adolescents than the Cycle 6 data, which were collected during an earlier time period. Moreover, when gender-matched adolescents of the 6th and 7th cycles were compared, for boys, there were no significant differences on the studied variables. The 7th cycle boys were less likely to have had sex with other boys than 6th cycle boys, but this difference was not statistically significant. However, the 7th cycle girls were found to be significantly older at first heterosexual contact and less likely to have been heterosexually active or pregnant; the 7th cycle girls were also significantly more likely to have used emergency contraception and to have had same-sex contact than 6th cycle girls. In the time interval between the 6th and the 7th cycles, the percentage of girls who had had sex with boys dropped notably, and the percentage of girls who had had sex with other girls increased from 5% to 10% (see Table 1).

These findings emphasize the importance of studying sexual behavior not only from the perspective of person-context interrelatedness, but also with a consideration of temporal-cultural factors (Bronfenbrenner & Morris, 2006). As we noted in our article, studies have shown considerable fluidity in the development and expression of sexual behavior and orientation over time, particularly in young women (Diamond, 2005, 2007, 2008; Diamond & Butterworth, 2008). The current comparison of 17-year-olds in the 6th and 7th cycles of the NSFG suggests that further exploration of factors that may be contributing to changing patterns of same-sex sexual behavior in American adolescents is warranted.