Ethical Issues and Practical Problems in Preimplantation Genetic Diagnosis

P reimplantation genetic diagnosis (PGD) is a newmethod of prenatal diagnosis that is developing froma union of in vitro fertilization (IVF) technology and molecular biology. Briefly stated, PGD involves the cre-ation of several embryos in vitro from the eggs and sperm of an interested couple. The embryos are permitted to de-velop to a 6-to-lO-cell stage, at which point one of the embryonic cells is removed from each embryo and the cel-lular DNA is analyzed for chromosomal abnormalities or genetic mutations. ' An embryo or several embryos found to be free of genetic abnormalities are subsequently trans-ferred to the woman's uterus for gestation. Fmbryos found to carry a genetic abnormality are discarded or frozen. Extra normal embryos may be frozen for future transfer or dona-tion to another couple. The rationale for this approach to prenatal diagnosis is straight-forward: "Preimplantation diagnosis for som