Scientific and ethical issues of preimplantation diagnosis

Preimplantation diagnosis (PID) offers couples at high risk of having offspring affected with a genetic disorder the possibility of an early prenatal diagnosis. For many couples this approach will give the opportunity to avoid a selective termination of affected pregnancies. Substantial advances were made in PID since the report, in 1990, of the first birth obtained after PID. Yet, many technical hazards have to be solved for PID to become a standard clinical tool. The very close correlation existing between the forthcoming developments in the fields of PID and human genome mapping will improve the reliability and efficiency of genetic diagnosis. In the near future, the procedure may also become easier and safer. As a consequence, the indications for PID could be extended to other genetic defects, such as multifactorial diseases. They could also be extended to cases with no medical background, such as social gender selection or behavioural traits. In this perspective, it is now time for both the medical and scientific communities to identify the ethical issues related to these potential new indications.