Genetic polymorphisms associated with the developmental timing of pubertal maturation and subsequent onset of sexual behavior in female adolescents

Previous genetic research has identified many human genes with allelic variation that are associated with differences in hormone synthesis. Still other non-genetic biological research has shown that increased levels of hormones are predictive of onset of puberty and that pubertal maturation is one of the strongest predictors of sexual activity onset. Studies informed by evolutionary theory have also shown that family context, such as the presence or absence of the biological father in early childhood, can predict pubertal maturation and, indirectly, subsequent sexual activity. This study was unique in that no research to date had attempted to use genetic markers as direct predictors of pubertal maturation and subsequent onset of sexual behavior in adolescents. Two genes of particular interest included the androgen receptor (AR) gene and the cytochrome P450c17-alpha gene (CYP17). Saliva samples (for genetic marker identification), pubertal status, and sexual behavior measures were gathered bi-annually from 248 post-menarcheal females over 2--3 years. Hierarchical linear modeling and growth curve analyses revealed that the A1/A1 allele of the CYP17 gene was predictive of the presence of a biological father, which predicted age at menarche. Later ages at menarche predicted lower onset level of sexual development and earlier ages at menarche predicted higher onset levels of sexual development; however, lower onset levels of sexual development predicted faster rates of sexual development. These findings show that genetic markers can be used to help identify variation in timing of pubertal development. Also, these results provide additional insight into understanding the differences in rates of sexual development among girls and suggest that there are mediating factors that may be buffering girls with higher onset levels of sexual development from progressing through sexual stages faster