A neuroendocrine predisposition for homosexuality in men.

In male rats, androgen deficiency during a critical hypothalamic organizational period was shown to give rise to a predominantly female-differentiated brain, homosexual behavior, and demonstration of a positive estrogen feedback effect. A positive estrogen feedback effect was also induced in intact homosexual men in contrast to intact heterosexual and bisexual men. Thus in 21 homosexual men an intravenous injection of 20 mg Presomen (Premarin) produced a significant decrease of serum LH levels followed by an increase above initial LH values. In 20 heterosexual and in five bisexual men, by contrast, intravenous estrogen administration, while producing a significant decrease of the serum LH level, was not followed by an increase above the initial LH values. Using a radioimmunoassay, plasma testosterone levels and 24-hr urinary excretions of unconjugated testosterone of adult homosexual men were found to be in the normal range as observed in heterosexual men. This finding suggests that homosexual men possess a predominantly female-differentiated brain which may be activated to homosexual behavior by normal or approximately normal androgen levels in adulthood.

Androsterone-etiocholanolone ratios in male homosexuals.

Analyses of 24-hour specimens of urine from healthy adult males for androsterone and etiocholanolone produced values which, when calculated as discriminant scores, discriminated between heterosexual and exclusively homosexual individuals. This confirms a previous study.No significant differences were found between heterosexuals and homosexuals in parental ages, secondary sex characteristics, genitalia, anthropometry, 17-ketosteroids, and 17-ketogenic steroids.A significant difference was found between the heterosexual group and homosexual group in the number of homosexual relatives in the immediate and extended families.

Endocrine function in male and female homosexuals.

Serial assays of hormones and their metabolites are reported in the urine of three male and four female homosexuals. Urinary testosterone levels were abnormally low in the two men who practised exclusive homosexuality and were within the normal range in the third, who had both homosexual and heterosexual relationships. In the women assays were generally performed throughout one menstrual cycle; in three the pattern of hormone excretion was ovulatory in character, while in the fourth evidence for ovulation was equivocal. Levels of testosterone and luteinizing hormone (L.H.) were raised in the female homosexuals, while those for oestrogens, particularly oestrone, were below the range for normal heterosexual subjects during their reproductive life; readings of follicle-stimulating hormone (F.S.H.) and pregnanediol were normal in three women. The data reported here are in keeping with the view that abnormalities in endocrine function may occur in both male and female homosexuals.