The Kinsey scale may be interpreted incorrectly to indicate that all people have a fixed, stable sexual orientation. In fact, sexual orientation is more accurately determined by patterns over time rather than at any given point in time (Baumgardner, 2007). Psychologist and researcher Lisa Diamond (2008a) uses the term sexual fluidity to describe variability in same-sex and other-sex attraction and/or involvement at various times and situations throughout the life span. Her research indicates that, for some women, sexual self-identity and the biological sex of preferred sexual partners can vary over time and experience unexpected transitions.

Lisa Diamonds research on sexual fluidity followed almost 80 women ages 18 to 25 over a 10-year period. At the beginning of the study, all the subjects were involved with other women and labeled themselves variably as lesbian, bisexual, or unlabeled. At the end of the study, about one third of the women were consistent in their self-identification as lesbian and in their attraction to and sexual involvement with women. However, the remaining women—initially self-identified as lesbian, bisexual, or unlabeled—had changed their self-identification at least once during the 10 years. Notably, these changes were variable: Lesbian changed to bisexual or unlabeled, bisexual changed to lesbian or unlabeled, unla­beled changed to bisexual or lesbian, and some previously self-identified lesbian, bisexual, and unlabeled changed to heterosexual. Some of the changes in self-labeling were due to sexual and/or romantic attraction to or involvement with men. However, the women who became involved with men continued to feel the same amount of attraction toward other women as they had at the beginning of the study 10 years earlier (Diamond, 2008b).

Conversely, women who have identified themselves as lesbians well into adulthood sometimes develop relationships with men. Feminist folksinger Holly Near and JoAnn Loulan, a longtime lesbian activist and the author of Lesbian Sex, were prominent in the gay community for many years prior to establishing relationships with men. This shift occurs often enough that a woman who becomes involved with a man

after being known as a lesbian may be labeled a "hasbian" (Diamond, 2008a; White, 2003).

For men, unless they identify themselves as bisexual, sexual fluid­ity between same-sex and other-sex attraction and relationships is less common than it is for women (Mock & Eiback, 2011). Scien­tists tend to agree that the male-female differences in sexual fluid­ity may be due to variations in biological developmental pathways (Diamond, 2008a). The extent to which the greater social stigma directed toward male homosexuality than toward female homosexu­ality restricts sexual fluidity in men is unknown, but it may also be an even more significant variable. As stigma toward male homosexu­ality continues to lessen, greater sexual fluidity in men may become apparent in younger men who tend to be more accepting of homo­sexuality. For example, in a large study of young people ages 12 to 25, males and females who identified as a sexual minority were equally likely to change their sexual orientation identity during the 13 years of the study (Ott et al., 2011).

Let’s now take a closer look at the four categories of sexual ori­entation—asexuality, bisexuality, homosexuality, and heterosexual­ity—keeping in mind the understanding that these are not static categories but are merely a way to orient ourselves when discussing the fluid and complex nature of our sexuality.