Researchers from the University of Washington say they could determine the complete DNA sequence of babies in the womb simply by analyzing blood samples from the mother and saliva samples from the father.
They confirmed their predictions by analyzing umbilical cord blood when the babies were born.
The new procedure can test for, among thousands of diseases, spina bifida and Down syndrome.
It could perhaps replace amniocentesis in which a probe is inserted through a woman's abdomen, extracting a small amount of amniotic fluid to test for abnormalities in the fetus.
ABC News contributed to this report.