No significant relationships were observed within females. This suggests that 2D:4D in adults may reflect, in part, neonatal testosterone exposure. The interaction of salivary testosterone and CAG repeat length also predicted change in left hand 2D:4D from 2 weeks to 12 months in males. In addition, the interaction of salivary T and CAG repeats predicted right hand digit ratio at 12 months and left hand digit ratio at 12 months and 24 months in males. This suggests that 2D:4D may not function well as a proxy measure of prenatal testosterone exposure in infancy. Sex differences were small compared to adults and did not consistently reach statistical significance. There was substantial variability across age in 2D:4D. In addition, 259 children provided DNA samples which were genotyped for the CAG repeat polymorphism in the androgen receptor. Saliva samples were collected from 236 of these children 3 months after birth and analyzed for testosterone. We collected 2D:4D ratios from 364 children between 0 and 2 years of age. The relative lengths of the 2 nd and 4 th digits (2D:4D) may provide an easily measurable and stable anthropometric index of prenatal androgen exposure, but no study has examined the development of 2D:4D in infancy and the potential impact of neonatal testosterone levels.
0 kommentar(er)
