In recent decades, the ways in which sexual minorities identify have changed dramatically. In response, social and health surveys have begun offering a greater range of response options within sexual orientation questions—for example, intermediate categories for “mainly heterosexual” and “mainly lesbian/gay” alongside the more common response options of “heterosexual,” “bisexual,” and “lesbian/gay.” Recent studies indicate that women who identify as “mainly heterosexual” report poorer health, greater health-risk behaviors, and higher rates of victimization than women identifying as “exclusively heterosexual.” However, we know very little about the demographic profile of women who choose the “mainly heterosexual” identity label compared to the adjacent “exclusively heterosexual” or “bisexual” labels or about changes over time in the prevalence and correlates of “mainly heterosexual” identification. This study addressed these knowledge gaps by modeling unique, high-quality survey data from three national cohorts of Australian women (Australian Longitudinal Study on Women’s Health, 2000–2017, n = 76,930 observations). Consistent with the facilitative environments model, we document stark cross-cohort increases in the percentage of Australian women identifying as “mainly heterosexual”—from ∼1% of those born in 1946–1951 to ∼26% of those born in 1989–1995, coinciding with comparable declines in the percentage of women identifying as “exclusively heterosexual.” We also found evidence of cohort differences in the associations between key sociodemographic factors—such as age, education, and socioeconomic status—and the likelihood of women identifying as “mainly heterosexual.” Finally, our results indicate that same-sex sexual attractions were more strongly associated with “mainly heterosexual” identification than was same-sex sexual behavior.

近几十年来，性少数群体的认同方式发生了巨大变化。作为回应，社会和健康调查开始在性取向问题中提供更广泛的回答选项——例如，“主要是异性恋”和“主要是女同性恋/男同性恋”的中间类别以及更常见的“异性恋”、“双性恋”和“女同性恋/男同性恋”。最近的研究表明，与被认定为“主要是异性恋”的女性相比，被认定为“主要是异性恋”的女性的健康状况更差、有更大的健康风险行为，而且受害率更高。然而，与相邻的“异性恋”或“双性恋”标签相比，我们对选择“主要是异性恋”身份标签的女性的人口统计资料知之甚少，也对“主要是异性恋”身份的流行率和相关性随时间的变化知之甚少。本研究通过对来自三个澳大利亚妇女全国队列的独特、高质量调查数据进行建模来解决这些知识差距（澳大利亚妇女健康纵向研究，2000-2017 年，n  = 76,930 个观察值）。与便利环境模型一致，我们记录了澳大利亚女性被认定为“主要是异性恋”的比例在跨队列中明显增加——从 1946-1951 年出生的人的约 1% 到 1989-1995 年出生的人的约 26%，与被认定为“完全异性恋”的女性比例的下降相吻合。我们还发现了关键社会人口因素（如年龄、教育和社会经济地位）与女性被认定为“主要是异性恋”的可能性之间关联的队列差异的证据。最后，我们的结果表明，与同性性行为相比，同性性吸引力与“主要是异性恋”认同的相关性更强。