Boys have higher weight and length at birth compared to girls. It is not known whether it is the result of chromosomal constitution or intrauterine androgenic action. Disorders/Differences of Sex Development (DSD) are an ideal model for assessing the influence of karyotype and intrauterine production or action of androgens on birth weight and length. The aim of this study was to verify the influence of Y chromosome and intrauterine androgens production or action on birth weight and length of children with DSD.