Amplification of fetal DNA in maternal plasma is a new way for non-invasive fetal genotyping in pregnancies at risk for disorders where the presence of a paternal DNA sequence contributes to the risk status of the fetus. We describe the use of a panel of 10 bi-allelic highly polymorphic markers to ascertain the presence and amplification of fetal DNA in case the fetus is negative for the targeted paternal "disease" sequence.