[7][8][9] There is no consensus on the exact cause of developing a sexual orientation, but genetic, hormonal, social, and cultural influences have been examined.
This could be attributed to females' higher erotic plasticity or to sociocultural factors that socialize women to be more open to change.
[15][16] The term and the concept gained recognition in the psychological profession[citation needed] and in the media.
[4][5][6] While the Centre for Addiction and Mental Health and American Psychiatric Association state that sexual orientation is innate, continuous or fixed throughout their lives for some people, but is fluid or changes over time for others,[18][19] the American Psychological Association distinguishes between sexual orientation (an innate attraction) and sexual orientation identity (which may change at any point in a person's life).
"[20] The American Psychiatric Association says individuals may "become aware at different points in their lives that they are heterosexual, gay, lesbian, or bisexual" and "opposes any psychiatric treatment, such as 'reparative' or 'conversion' therapy, which is based upon the assumption that homosexuality per se is a mental disorder, or based upon a prior assumption that the patient should change his/her homosexual orientation".
For some of 100 non-heterosexual women she followed in her study over a period of 10 years, the word bisexual did not truly express the versatile nature of their sexuality.
In Maccio's (2011) review of sexual reorientation therapy attempts, she lists two studies that claim to have successfully converted gay men and lesbians to heterosexuals and four that demonstrate the contrary.
The study consisted of 37 former conversion therapy participants (62.2% were male) from various cultural and religious backgrounds who currently or previously identified as lesbian, gay, or bisexual.
This study stands as support for the biological origin of sexual orientation, but the largely male sample population confounds the findings.
[25] Many retrospective studies looking at childhood behavior are criticized for potential memory errors;[26] so a study by Rieger, Linsenmeier, Gygax, & Bailey (2008) used home videos to investigate the relationship between childhood behaviors and adult sexual orientation.
[28] Similarly, a study has shown that homosexual men have a sexually dimorphic nucleus in the anterior hypothalamus that is the size of females'.
[11] One study by Steven E. Mock and Richard P. Eibach from 2011 shows 2% of 2,560 adult participants included in National Survey of Midlife Development in the United States reported change of sexual orientation identities after a 10-year period: 0.78% of male and 1.36% of female persons that identified themselves to be heterosexuals at the beginning of the 10-year period, as well as 63.6% of lesbians, 64.7% of bisexual females, 9.52% of gay males, and 47% of bisexual males.
According to the study, "this pattern was consistent with the hypothesis that heterosexuality is a more stable sexual orientation identity, perhaps because of its normative status.
Having only adults included in the examined group, they did not find the differences in fluidity which were affected by age of the participants.
[35] In western culture, women are also expected to be more emotionally expressive and intimate towards both males and females.
According to this view, women are capable of forming romantic bonds with both sexes and sexual fluidity may be explained as a reproductive strategy that ensures the survival of offspring.
[33] One study that did compare the stability of youth sexual orientation identity across genders found results opposite to most done with adult samples.
Rosario et al. (2006) conclude that "acceptance, commitment, and integration of a gay/lesbian identity is an ongoing developmental process that, for many youths, may extend through adolescence and beyond.
"[38] Sabra L. Katz-Wise and Janet S. Hide report in article published 2014 in "Archives of Sexual Behavior" of their study on 188 female and male young adults in the United States with a same-gender orientation, aged 18–26 years.