1. Department of Epidemiology, University of North Carolina Gillings School of Global Public Health, Chapel Hill, North Carolina. 1
2. Center for Gastrointestinal Biology and Disease, University of North Carolina School of Medicine, Chapel Hill, North Carolina. 2
3. Department of Geography, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina. 3
4. Department of Health Policy and Management, University of North Carolina Gillings School of Global Public Health, Chapel Hill, North Carolina. 4
5. Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina. 5
6. Department of Pediatrics, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina. 6
7. Shady Grove Fertility, Raleigh, North Carolina. 7
8. Division of Reproductive Endocrinology and Infertility, Department of Gynecology and Obstetrics, Johns Hopkins University School of Medicine, Baltimore, Maryland. 8