Monozygotic twins from in vitro fertilization.

A case of identical twins following in vitro fertilization and embryo transfer ( IVF -ET) is described. Two embryos were transferred, but it is apparent that only one implanted and subsequently divided in the early implantation phase to produce identical male twins within a monochorionic , diamniotic placental and membrane configuration. Additional marker studies provide an overall probability of less than 0.001 for dizygosity . There is unlikely to be any relationship between this event and the technique of IVF -ET.