1. Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts, USA
2. Department of Obstetrics and Gynecology, Division of Reproductive Endocrinology and Infertility, Harvard Medical School/Massachusetts General Hospital Fertility Center, Boston, Massachusetts, USA
3. Department of Biostatistics, Harvard School of Public Health, Boston, Massachusetts, USA
4. National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, Georgia, USA