The GENS Project is a study of sex differences in gene function funded by the Johns Hopkins Women’s Health Research Group and The Foundation for Gender-Specific Medicine. Growing research evidence suggests that hormones impact the formation of the embryonic and fetal brain. This study will explore if prenatal hormone exposure leaves an epigenetic mark via alterations to DNA methylation, a measure of gene functional capacity.  We are especially interested in how prenatal hormone action at the genetic level may be different for male and female fetuses.