title: The roots of innovation.
mesh_terms: D003276:Contraceptives, Oral; D004059:Diffusion of Innovation; D006801:Humans; D012106:Research; D012109:Research Support as Topic; D012189:Retrospective Studies; D013997:Time Factors; D006113:United Kingdom; D014481:United States
chemical_list: D003276:Contraceptives, Oral