The American Psychological Association states that "sexual orientation falls along a continuum.In other words, someone does not have to be exclusively homosexual or heterosexual, but can feel varying degrees of both.
Bisexuality as a transitional identity has also been examined.
In a longitudinal study about sexual identity development among lesbian, gay, and bisexual (LGB) youths, Rosario et al.
"found evidence of both considerable consistency and change in LGB sexual identity over time".
Youths who had identified as both gay/lesbian and bisexual prior to baseline were approximately three times more likely to identify as gay/lesbian than as bisexual at subsequent assessments.
Of youths who had identified only as bisexual at earlier assessments, 60 to 70 percent continued to thus identify, while approximately 30 to 40 percent assumed a gay/lesbian identity over time. suggested that "although there were youths who consistently self-identified as bisexual throughout the study, for other youths, a bisexual identity served as a transitional identity to a subsequent gay/lesbian identity." By contrast, a longitudinal study by Lisa M.