In 2008, 1 in 88 children in the United States has been identified with autism spectrum disorders (ASDs) across all racial, ethnic, and socioeconomic groups. ASD is a life-long complex neuropsychiatric disease that affects the individual and the family with no known cause or cure. Furthermore, ASD occurs more commonly in males, with a male to female ratio of 4:1. Specific causal factors leading to the higher male prevalence in ASD remain unclear. This project will be based in the Early Autism Risk Longitudinal Investigation (EARLI), an enriched-risk autism pregnancy cohort collecting data on potential risk factors and biomarkers for ASDs during pre-, peri-, neonatal and early infancy periods. Enrolled subjects are mothers of a child with an ASD at the start of a subsequent pregnancy. Data from 175 mother-infant sibling pairs will be available for analysis. This project analyzes baby's first stool and cord blood for male hormone and also analyzes mother's pregnancy urine for common chemicals that mothers may be exposed to through the use of personal care products containing antimicrobials that are believed to possibly raise levels of male hormone. First, estimates of male hormone in cord blood and baby's first stool will be compared to investigate absolute individual and relative average gender differences based on measuring hormones in these two different samples. Second, associations will be estimated between male hormone level in cord and first stool sample and AOSI scores at 12 months (which measure a range of behaviors associated with autism risk). Third, prenatal male hormone levels will be examined to see if they are influenced by the amount of exposure to the chemical a mother has during pregnancy. The analysis will also consider a number of other factors in order to make sure differences in these do not account for the results (these include: sex, gestational age, pregnancy alcohol use, pregnancy smoking, birth order and mother's age).