Despite the controversial discussions, which have accompanied it since its first introduction of into clinical medicine particularly in Switzerland, assisted reproductive medicine has come to acquire a firm standing in present-day society. This broad acceptance is the logical consequence of the availability of efficient methods of family planning which started with the introduction of oral contraception in the early sixties. Over time assisted reproductive medicine has grown with a considerable degree of efficacy due to improvements in the culture conditions in the embryology laboratory and due to sophisticated ovarian hyperstimulation. In conjunction with steadily rising treatment numbers the latter has contributed to a high incidence of multiple deliveries, which now is considered a complication of assisted reproduction and current opinion demands that multiple pregnancies must be avoided as much as possible. The experience in various countries has demonstrated that through the selection of one single embryo with high developmental capacity the incidence of multiple gestations can be lowered to virtually none. However, the restrictive legislations in vigour both in Switzerland and in Germany impede such an endeavour. Still, the significantly higher pregnancy rates achieved by extending the culture of embryos up to the blastocyst stage clearly demonstrate that embryology holds the clues to further considerable improvements of assisted reproductive technology. Through the rapid development of three-dimensional culture techniques, immature ovarian follicles e.g. primordial follicles may be cultured up to the mature Graafian stage thereby avoiding the need to stimulate the ovaries.