Iatrogenic - physician-made - multiple pregnancies (IMPs) significantly contribute to the epidemic of twins and high-order multiples in most developed and in many developing countries. The primary etiology for IMPs is treatment of reduced fecundity, some but not all of which is associated with specific lifestyle changes of women in the second half of the 20th century. IMPs contribute to increased perinatal morbidity and mortality related to prematurity and low birth weights. In addition, the use of assisted conception techniques increases the frequency of monozygotic twinning and related pathology. Because assisted conceptions are costly interventions, current numbers of IMPs represent a balance between the need to maximize success rates and the desire to minimize the untoward outcome rates. We believe that eliminating procedures associated with unavoidable IMPs and controlling the number of transferred embryos can achieve a significant reduction in the adverse perinatal outcomes and costs associated with IMPs.