The LGBT Health & Development Program


Genetic and environmental influences on pubertal development: Longitudinal data from Finnish twins at ages 11 and 14

3rd February

Abstract
To study sources of individual differences in pubertal development, the authors fit a sex-limitation common factor model to data reported, at ages 11 and 14 years, by 1,891 twin pairs on items that comprise the Pubertal Development Scale (PDS; A. C. Petersen, L. Crockett, M. Richards, & A. Boxer, 1988). The model divides variation into a general pubertal factor and item-specific variation and, in addition, decomposes it into constituent sources. In both boys and girls, genetic influences made the largest contribution to variance common to PDS items. Genetic and nonshared environmental factors accounted for variation specific to PDS items in boys, whereas for girls, common environmental influences were added for growth spurt and menarcheal status. For both common and item-specific variation, genetic effects were partially sex specific. Subsidiary analyses found accelerated maturation in both boys and girls who … Read More »



A candidate gene study of CYP19 (aromatase) and male sexual orientation.

3rd February

Abstract
Aromatase cytochrome P450 (CYP19), which is necessary for the conversion of androgens to estrogens, plays an important role in the sexual differentiation of the brain. To investigate whether differences in the gene encoding the aromatase enzyme influence sexual orientation in men, we conducted linkage, association, and expression analyses in a large sample of homosexual brothers using microsatellite markers in and around CYP19. No linkage was detected, and a gene-specific relative risk of 1.5-fold could be excluded at a lod score of -2. Results of the TDT demonstrated no preferential transmission of any of the CYP19 alleles in this sample. Expression of aromatase mRNA by microarray analysis was not significantly different between heterosexual and homosexual men. These results suggest that variation in the gene for this subunit of the aromatase enzyme complex is not likely to be a major factor in … Read More »






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