Preimplantation polar body diagnosis makes it possible to detect and avoid genetic and chromosomal disorders before pregnancy. We have shown that the polar body biopsy does not affect fertilization and viability of the resulting embryos. Our present experience of polar body diagnosis includes 187 clinical cycles, performed for preimplantation diagnosis of cystic fibrosis, alpha-1-antitrypsin deficiency, Tay-Sach's disease, retinitis pigmentosa, hemophilia A, Alport and sickle cell disease, and common aneuploidy, using the FISH technique. Over three-quarters of these cycles have resulted in embryo transfer, 38 in clinical pregnancy and 12 in the birth of an unaffected child. The present review describes the results of our clinical trial on the polar body diagnosis of genetic and chromosomal disorders, demonstrating the reliability of polar body genetic analysis for preimplantation diagnosis.