Sexual orientation has 'in between' groups, study shows

Sexual orientation is best represented as a continuum that has two new categories -- "mostly heterosexual" and "mostly gay/lesbian" -- in addition to heterosexual, bisexual or gay/lesbian, according to a new Cornell study.

In a study of 1,676 responses to an online sexuality survey advertised on Facebook, which included questions about sexual orientation identity, sexual attraction and sexual partners, 20 percent of women and 9 percent of men identified themselves as "mostly heterosexual." Researchers say that this finding supports using the more nuanced 5-point scale for depicting sexual orientation.

The findings also suggest that sexual orientation is not just a one-dimensional continuum with preference for opposite sex on one end and for the same sex on the other. It is more accurately conceptualized with two continuums, they say -- one for depicting a person's orientation to the same sex and the other for the opposite sex.

"In other words, having more same-sex sexuality does not necessarily mean having less opposite-sex sexuality," said sexuality expert Ritch Savin-Williams, professor of human development in Cornell's College of Human Ecology, who conducted the study with lead author and graduate student Zhana Vrangalova.

The research is published in the February issue of Archives of Sexual Behavior.

The researchers also found that some people who chose either of the two presumably exclusive sexual orientation identities (heterosexual and gay/lesbian) still reported some non-exclusivity in their attractions and/or behavior. Although the researchers did not use a representative sample of U.S. adults, their findings are similar to other investigations based on national samples, they noted.

"We've known for some time that gays, lesbians and bisexuals face common and unique health challenges, and now emerging evidence indicates that people identifying themselves as mostly heterosexual do as well," Savin-Williams said.

Using more accurate sexual orientation labels in health surveys and research will help understand the real-world repercussions of sexuality on physical, sexual, mental and social health, he said.

"It is very encouraging to see more and more investigators including these 'in-between' labels in their studies. The next step is to examine these labels in greater depth and understand what they mean to people and how they shape their lives," Vrangalova said.

The research was supported by the Departments of Human Development and of Psychology.