Bisexuality in women could be a lifelong orientation a new study suggests.

The finding runs counter to the idea that bisexuality is an experimental or transitional period for women who, for instance, are uncertain or have fear of commitment.

"These findings demonstrate that the distinction between lesbianism and bisexuality is a matter of degree rather than kind," writes University of Utah psychologist Lisa Diamond in the January issue of the journal Developmental Psychology.

To some, a finding of bisexuality as a separate sexual orientation may seem like a no-brainer. But among many scientists and members of the public, bisexuality has been defined by stereotypes and unfounded assumptions.

"There were clearly some theorists who suggested that bisexuality is a transitional stage, but that was largely based on anecdotal, rather than empirical, data," said psychologist M. Paz Galupo, director of LGBT (Lesbian, Gay, Bisexual and Transgender) Studies at Towson University in Maryland. "This view is popularized, also, by the stereotypes that our culture holds regarding bisexual individuals."

Diamond surveyed 79 women aged 18 to 25 who considered themselves bisexual or lesbian, or who refused any label for their sexual orientation. She interviewed the women five times over a 10-year period from 1995 through 2005. Respondents gave detailed information on their sexual identities, attractions, behaviors and their social and familial relationships.

Diamond found bisexual and unlabeled women were more likely than lesbians to change their sexual identity over the 10 years. The bisexual or unlabeled women tended to switch between bisexual and unlabeled rather than to lesbian or heterosexual.

Nearly 20 percent of respondents switched from a bisexual or unlabeled identity to heterosexual, but more than half of these women switched back to bisexual or unlabeled.

(Agencies via Xinhua February 4, 2008)