Sex determination, differentiation, and identity

Clinical and Laboratorial Features That May Differentiate 46,XY DSD due to Partial Androgen Insensitivity and 5α-Reductase Type 2 Deficiency

The aim of this study was to search for clinical and laboratorial data in 46,XY patients with ambiguous genitalia (AG) and normal testosterone (T) synthesis that could help to distinguish partial androgen insensitivity syndrome (PAIS) from 5α-reductase type 2 deficiency (5α-RD2) and from cases without molecular defects in the AR and SRD5A2 genes. Fifty-eight patients (51 families) were included. Age at first evaluation, weight and height at birth, consanguinity, familial recurrence, severity of AG, penile length, LH, FSH, T, dihydrotestosterone (DHT), Δ4-androstenedione (Δ4), and T/DHT and T/Δ4 ratios were evaluated. The AR and SRD5A2 genes were sequenced in all cases. There were 9 cases (7 families) of 5α-RD2, 10 cases (5 families) of PAIS, and 39 patients had normal molecular analysis of SRD5A2 and AR genes. Age at first evaluation, birth weight and height, and T/DHT ratio were lower in the undetermined group, while penile length was higher in this group. Consanguinity was more frequent and severity of AG was higher in 5α-RD2 patients. Familial recurrence was more frequent in PAIS patients. Birth weight and height, consanguinity, familial recurrence, severity of AG, penile length, and T/DHT ratio may help the investigation of 46,XY patients with AG and normal T synthesis.

Prenatal exposure to sex steroid hormones and behavioral/cognitive outcomes

Experimental studies in animals indicate that androgen exposure in fetal or neonatal life largely accounts for known sex differences in brain structure and behavior. Clinical research in humans suggests similar influences of early androgen concentrations on some behaviors that show sex differences, including play behavior in childhood and sexual orientation in adulthood. Available research also suggests that sex steroid hormone exposure may contribute to sex differences in the risk of autism and affective disorders in schizophrenia. However, findings have been inconsistent for other characteristics that show sex differences, including aggression and spatial ability. Moreover, social and environmental factors may modulate some of the associations observed. This article reviews the evidence that early-life exposure to sex steroid hormones contributes to sexually dimorphic behavior and cognitive abilities in humans.

Sex differences in child-onset, life-course-persistent conduct disorder. A review of biological influences

Sex is widely acknowledged to be an important factor in understanding many aspects of behavior, not the least of which is antisocial behavior. When antisocial behavior manifests itself in the domain of juvenile psychopathology, it often takes the form of a type of conduct disorder (CD) that begins in childhood and is life-course-persistent. There is an overwhelming consensus that there is a massive male preponderance in this type of CD and that biological variables are major influences on this difference. This review built on this consensual scaffolding in an attempt to provide some useful leads for identifying the biological contributions to the predominantly male complexion of life-course-persistent CD by linking it to three different levels of biological mechanisms.

Idiopathic male pseudohermaphroditism is associated with prenatal growth retardation

About 50% of intersex cases are due to male pseudohermaphroditism, and of these cases, 50% are not clarified aetiologically. The association of idiopathic male pseudohermaphroditism and prenatal growth retardation has been recently reported. The aim of this study was to verify whether there was a difference in weight and/or length at birth between idiopathic and non-idiopathic male pseudohermaphroditism patients. A total of 70 patients with male pseudohermaphroditism were recruited; 35 non-idiopathic and 35 idiopathic. Birth weight and length were converted to z scores, and the severity of genital ambiguity was classified according to Prader grades: less virilized (Prader 1 to 3) and more virilized (Prader 4 or 5). Data were analysed using a Mann-Whitney test, odds ratio and logistic regression analysis. Birth weight (P = 0.028) and length (P = 0.01) z scores were lower in the idiopathic male pseudohermaphroditism group compared to the non-idiopathic group and were also significantly decreased among the less virilized patients, both in the sample as a whole (weight z score, P = 0.002; length z score, P = 0.0008) and in the group of idiopathic patients (weight z score, P = 0.013; length z score, P = 0.007). According to logistic regression analysis, only birth length z score significantly predicted the severity of the genital ambiguity in patients with idiopathic male pseudohermaphroditism ( P = 0.0007).

CONCLUSION

There is an association between prenatal growth retardation and male pseudohermaphroditism which may be due to genetic factors not clarified yet or to environmental factors which act early in gestation.

Prenatal sex hormone effects on child and adult sex-typed behavior: methods and findings

There is now good evidence that human sex-typed behavior is influenced by sex hormones that are present during prenatal development, confirming studies in other mammalian species. Most of the evidence comes from clinical populations, in which prenatal hormone exposure is atypical for a person's sex, but there is increasing evidence from the normal population for the importance of prenatal hormones. In this paper, we briefly review the evidence, focusing attention on the methods used to study behavioral effects of prenatal hormones. We discuss the promises and pitfalls of various types of studies, including those using clinical populations (concentrating on those most commonly studied, congenital adrenal hyperplasia, androgen insensitivity syndrome, ablatio penis, and cloacal exstrophy), direct measures of hormones in the general population (assayed through umbilical cord blood, amniotic fluid, and maternal serum during pregnancy), and indirect measures of hormones in the general population (inferred from intrauterine position and biomarkers such as otoacoustic emissions, finger length ratios, and dermatoglyphic asymmetries). We conclude with suggestions for interpreting and conducting studies of the behavioral effects of prenatal hormones.