For the second time in a month scientists say a simple blood test can detect abnormalities in a fetus.
The technique is even more streamlined than one announced a few weeks ago -- which requires a father's saliva and a mother's blood.
This latest method, reported in the journal "Nature", can be done without knowing who the father is, much less obtaining a sample of his DNA.
The father-free method promises to make fetal sequencing possible in every pregnancy.
Determining a fetus's genome might give women more reasons to end a pregnancy, but researchers say it would also let doctors identify conditions that can be treated before birth or immediately after.
