Sexual Inversion is implicated in True or HomoSexual Transsexualism (HSTS) and Transgender Homosexuality, that is, feminine male homosexuality and masculine female. It is innate, has distinctive features and should be considered a form of Intersex.
Males with Sexual Inversion may develop either into Transgender Homosexuals (feminine male/masculine female) or they may develop fully into women. In males this phenomenon is usually associated with a range of physical effects including, but not limited to: lightness of build; tendency to be smaller than related males; fineness of bony structures; anomalies in digit ratios such that they tend to resemble the female typical, marked neoteny (baby face) and usually, delayed masculinisation even after puberty.
Homosexual transsexuals exactly fit the profile of ‘sexual inversion’ as defined over a hundred years ago by Karl Heinrich Ulrichs (1825-1895)
‘The truth of the invert was inside rather than on the surface; thus a male invert was “really” a woman, and should be allowed to express a female gender, and a female invert was “really” a man, and should be allowed to dress and live as one. Inversion also referred to the ways in which such bodies inverted the laws of nature, which supposedly decreed that male bodies should desire female sexual partners instead of male ones, and vice versa. The theory of sexual inversion maintained conventional categories of sexuality and gender and did not allow one to be divided from the other. Inversion meant that a man’s homosexual desires, effeminacy, or both did not challenge masculine gender or heterosexual sexual norms; rather, a perfectly normal heterosexual woman with a feminine gender was trapped inside him, yearning to come out.’ (Encyclopedia.com)
Later, the English sexology pioneer H Havelock Ellis wrote:
‘(Congenital sexual inversion) is sexual instinct turned by inborn constitutional abnormality towards persons of the same sex.'(My emphasis).
(Ellis uses the term ‘congenital’ which remains unproven. It is clear that what he is talking about is innate and must result from biological factors occurring either in the womb or shortly after birth; but we do not know whether the trigger for whatever these might be is congenital, that is, a result of a specific gene mutation. However, the condition is innate and not acquired. I prefer to use the term ‘innate’.)
Ellis’ massive study of human sexuality, Studies in the Psychology of Sex, which is downloadable via this page HERE, contains a whole volume on sexual inversion, and he defines this as above on the first page. Note that both Ulrichs and Ellis agreed that this sexual inversion was innate. It was inborn and not a matter of choice.