More than 20 years ago, a doctor who was curious about the effects of long-term oral contraceptive use sent questionnaires to 370,000 registered nurses. The answers he and colleagues recieved have
Links:
[1] http://admin.indiaenvironmentportal.org.in/news/one-doctor-370000-nurses-and-bounty-findings
[2] http://admin.indiaenvironmentportal.org.in/category/thesaurus/health