1. Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, Michigan, USA
2. Department of Statistics, North Carolina State University, Raleigh, North Carolina, USA
3. Obstetrics, Gynecology and Reproductive Biology, Brigham and Women´s Hospital, Harvard Medical School, Boston, Massachusetts, USA
4. Department of Epidemiology, Harvard School of Public Health, Boston, Massachusetts, USA
5. Channing Laboratory, Department of Medicine, Brigham and Women´s Hospital, Harvard Medical School, Boston, Massachusetts, USA
6. Department of Biostatistics, Harvard School of Public Health, Boston, Massachusetts, USA
7. Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts, USA
8. Vincent Memorial Obstetrics and Gynecology Service, Andrology Laboratory and in Vitro Fertilization Unit, Massachusetts General Hospital, Boston, Massachusetts, USA