1. Department of Epidemiology and Biostatistics, Arnold School of Public Health, University of South Carolina, Columbia, SC, USA
2. Department of Health Management and Policy, College of Public Health, University of Iowa, Iowa City, IA, USA
3. Statistics and Epidemiology, RTI International, Research Triangle Park, NC, USA
4. Serviço de Aconselhamento Genético - IBB/UNESP, São Paulo State University, Botucatu, SP, Brazil
5. Department of Pediatrics, Division of Neonatology, University of Iowa, Iowa City, IA, USA
6. Departments of Health Management and Policy, Economics, and Preventive & Community Dentistry, and Public Policy Center, University of Iowa, Iowa City, IA, USA
7. National Bureau of Economic Research, Cambridge, MA, USA