For early antenatal diagnosis, chorionic villus sampling (CVS) represents a valid alternative to early amniocentesis. It gives rapid results with minimal increase in risks (miscarriage about 1.5 p. cent). The indications of CVS are therefore likely to broaden. For late antenatal diagnosis, linked to an echographic or clinical anomaly, sampling of fetal blood by funicular puncture is taking precedence over sampling of amniotic fluid. Results can be obtained easily and much more quickly at low risk (about 1 p. cent). These techniques are in no way alternatives, but rather complement one another. It is always advisable to choose with care the technique that offers the greatest information with maximum safety.