Interest in mechanisms of embryo implantation is increasing, particularly with the realization that failure of implantation after in vitro fertilization and embryo transfer places significant limits on the success of treatment. In addition, there is a need to provide hypotheses, and ultimately mechanisms, for the high rates of embryonic loss in women in the population at large. Traditionally, implantation research has concentrated on genetics and endocrinology without providing many therapeutic benefits. A new era is now beginning with the application of modem cellular and molecular...