Birth defects are present in 3-6% of live born humans and in greater numbers in those that die during gestation. Birth defects are the leading cause of infant death and are more prevalent than most chronic childhood diseases. The causes of birth defects are largely unknown with genetic and environmental factors, and a combination of these, proven and suspected to be the cause. We are identifying genetic and environmental factor that cause vertebral column and heart defects in human and mouse. We have evidence of gene-environment interaction in mouse causing developmental defects in mice.