Animal studies reveal that almost all antineoplastic agents are teratogenic. But extrapolation to human beings is not simple because of species differences. Few human data are available, most are sporadic case reports. Other toxic effects for the fetus and neonate (intrauterine exposure during second and third trimester) must be taken in consideration when prescribing chemotherapy for pregnant women. Adverse effects observed in adult and children are helpful if data during fetal life are lacking. Long-term studies are needed to evaluate the transplacental effects of chemotherapy during pregnancy; these studies should assess the child's mental and physical development, infertility and the occurrence of second malignancies.