"In the 1940s, alarm about the worlds burgeoning population, and the naive belief that the phenomenon could be curbed by the introduction of improved contraceptive methods, led to extensive research in the USA. The results of these endeavors were the pill and the plastic IUD. Plastic devices solved the problem inherent in the insertion and retrieval of the Rings of Gräfenberg and Ota. Made of thermoplastics, the new IUDs were given a memory of their original shape, could be straightened to fit inside a narrow straw-type inserter tube and regained their initial contour after introduction into the uterus. The notion that intrauterine contraception is safe and effective was proven in the early 1960s by the medical statistician Dr Christopher Tietze (1908-84), a Jewish emigrant to the USA, and a great admirer of Gräfenberg (Figure 2). Having collected and analyzed clinical results obtained with the Gräfenberg and Ota Rings, Dr Tietze organized the first international symposium on intrauterine contraception in New York City in 1962, sponsored by the Population Council. At the conference, the pioneers of the plastic devices, Dr Margulies and Dr Lippes, were invited to demonstrate their invention and report preliminary clinical results."