Studies on Human Sexual Development. II. Fetal and Maternal Serum Gonadotropin and Sex Steroid Concentrations¹

Testosterone levels in umbilical cord blood, maternal peripheral plasma and amniotic fluid of the crab-eating monkey (Macaca fascicularis)

“…It should be noted that the Leydig cells also began involution at about day 75 of gestation (Fouquet, Dang and MeusyDessolle, 1978 Up to now, all the AFT data on humans reported by different laboratories are consistent with the present findings which are reported for the first time on another primate. UAPT in humans is higher in male fetuses before mid-gestation than in females ; this difference then decreases and finally disappears around term (Mizuno et al,1968 ;Rivarola, Forest and Migeon, 1968 ;Saez and Bertrand, 1969 ;Abramovich and Rowe, 1973 ;Reyes et at., 1974). AFT level progresses in the same way (Saez and Bertrand, 1969 ;Younglai, 1972 ;Younglai and Lin, 1973 ;Frasier, Weiss and Horton, 1974 ;Giles et al, 1974 ;Judd et al, 1976 ;Belisle, Fencl and Tulchinsky, 1977 ;Robinson et al, 1977 ;Zondek, Mansfield and Zondek, 1977 (Fouquet, Dang and Meusy-Dessolle, 1978), is the testosterone found of testicular origin ?…”

Homosexuality as a Consequence of Epigenetically Canalized Sexual Development

“…After this time, fetal secretion of T by the testes declines markedly, causing average T values in males to become indistinguishable from levels in females (Reyes et al 1974). Although male fetuses have higher average T than females starting around week 11, overlap in T levels between the sexes (i.e., some XX fetuses having higher T than some XY fetuses) was observed at all times except between weeks 15-19 (Reyes et al 1974). This transient lack of overlap (and hence an unambiguous signal of fetal gender) may be genuine or an artifact due to small sample size.…”

“…Secretion of T by the testes increases its concentration in the blood of XY fetuses. The maximum average difference in T concentration between male (XY) and female (XX) fetuses occurs between weeks 11-17 (Reyes et al 1974). After this time, fetal secretion of T by the testes declines markedly, causing average T values in males to become indistinguishable from levels in females (Reyes et al 1974).…”

“…The maximum average difference in T concentration between male (XY) and female (XX) fetuses occurs between weeks 11-17 (Reyes et al 1974). After this time, fetal secretion of T by the testes declines markedly, causing average T values in males to become indistinguishable from levels in females (Reyes et al 1974). Although male fetuses have higher average T than females starting around week 11, overlap in T levels between the sexes (i.e., some XX fetuses having higher T than some XY fetuses) was observed at all times except between weeks 15-19 (Reyes et al 1974).…”

“…The human male phallus and female vulva are formed during weeks 9 -15 of gestation, although the phallus requires T to continue to grow during later fetal development (summarized in Wilson et al 1981). During this time of genital differentiation, data on fetal T collected by Reyes et al (1974) show high overlap in T concentrations between the sexes. The same relationship is found in the rat, in which T concentrations strongly overlap between the sexes during the time (and all points previous) when the phallus and vulva are differentiating (Weisz and Ward 1980).…”