1. Clinical Research Branch, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, USA
2. Social & Scientific Systems, Inc., Durham, NC, USA
3. Reproductive Endocrine Unit, Massachusetts General Hospital, Boston, MA, USA
4. Department of Pathology, Massachusetts General Hospital, Boston, MA, USA
5. Department of Pathology, Women and Infants Hospital and the Alpert Medical School of Brown University, RI, USA