Freud characterized homosexuality as “inversion” – that all humans are born bisexual but unresolved oedipal conflicts and a failure to break the maternal bond in early years develops into adult homosexuality. (Freud 1975: 5). According to Gagnon, sexuality is learnt on the basis of script templates conditioned by the norms of social behaviour and individual interpretation. (Gagnon 1990:6). Bozett and Sussman (1989) offer insight on several studies indicating the negative feedback that homosexuals receive from society and their own families, arising from religious notions that it is an aberrant and evil condition. These studies appear to support the learned model of sexual behaviour.
Studies have shown that differences in brain structure between homosexual and heterosexual men. LeVay(1991) found neuroanatomic differences between homosexual and heterosexual males. The interstitial nucleus of the anterior hypothalamus – the INAH3 – was similar to women in homosexual men – three times larger than heterosexual men. Swaab et al (1995) found that the suprachiasmatic nuclear area of the homosexual hypothalamus contained double the number of cells, thereby corroborating the possible influence of brain structure on homosexuality. Honekopp et al (2007) have recently corroborated earlier studies on prenatal androgenization of human behaviour, as reflected in the relative length of the index finger to the ring finger. Hall and Kimura (1994) examined the relationship between dermatoglyphic asymmetry or fingerprint markers and sexual orientation. They found that only homosexual men demonstrated a tendency towards leftward asymmetry. Similarly, Allen and Gorski (1992) found that the anterior commissure in the brain is typically larger in homosexual men, just as in the case of women. The functional implications of the last two studies are not clear, however, differences in brain plasticity may play a role in sexual orientation. .