This illustrates that male and female homosexuality are different phenomena, something which is also apparent by (a) the greater prevalence of male compared to female homosexuality, and (b) the much more obvious behavioral cues of male compared to female homosexuals.
As I wrote in the old Dodona forum in 2004, distinguishing between male and female homosexuality:
Some boys are naturally effeminate or girly and are more prone to develop an abnormal sexuality during their childhood. Homosexuality is a mental illness but one which is difficult to treat because it starts early on and becomes a part of a person's core personality by the time he becomes an adult. While most men learn to act like men as part of the growin up process, homosexuals must unlearn their whole development and relearn a sexual role, something which is virtually impossible.Journal of Biosocial Science (forthcoming)
For lesbians, the cause is probably ugliness or fear of men. While male homosexuals often have a 'normal' appearance, lesbians tend to be unattractive -- except in porn movies of course.
MASCULINITY–FEMININITY PREDICTS SEXUAL ORIENTATION IN MEN BUT NOT IN WOMEN
J. RICHARD UDRY a1 and KIM CHANTALA
Using the nationally representative sample of about 15,000 Add Health respondents in Wave III, the hypothesis is tested that masculinity–femininity in adolescence is correlated with sexual orientation 5 years later and 6 years later: that is, that for adolescent males in 1995 and again in 1996, more feminine males have a higher probability of self-identifying as homosexuals in 2001–02. It is predicted that for adolescent females in 1995 and 1996, more masculine females have a higher probability of self-identifying as homosexuals in 2001–02. Masculinity–femininity is measured by the classical method used by Terman & Miles. For both time periods, the hypothesis was strongly confirmed for males: the more feminine males had several times the probability of being attracted to same-sex partners, several times the probability of having same-sex partners, and several times the probability of self-identifying as homosexuals, compared with more masculine males. For females, no relationship was found at either time period between masculinity and sex of preference. The biological mechanism underlying homosexuality may be different for males and females.