If the two polar bodies in an egg cell are examined, it can be seen whether the chromosomes are damaged or whether the positions of the chromosomes are abnormal. This should help to prevent pregnancies and births of severely ill children and lead to higher implantation and birth rates.

Preimplantation diagnosis (PID) on the individual cells of a developing embryo allows the hereditary material to be examined directly. In Germany, PID is thought to be incompatible with the German Embryo Protection Act. This is why polar body diagnosis has become established in parallel to the debate on ethical and legal issues. In the accompanying editorial, the human geneticist Peter Propping asks whether it is honest that German doctors continue to draw on PID results obtained abroad to compare the reliability of polar body diagnosis.-Deutsches Aerzteblatt International