Called comparative genomic hybridization, the tests use so-called "gene chips" to detect chromosomal variations than standard prenatal testing cannot detect, The Washington Post reported Sunday.
"We can interrogate the fetal genome to identify smaller pieces of DNA that are either added or subtracted, and many of these can cause disease," said Ronald J. Wapner of Columbia University, who is leading a $3.3 million federally funded study that is starting to evaluate the technology in 4,000 pregnancies.
While proponents say the technology helps couples to identify abnormalities soon enough to terminate the pregnancy or prepare to care for an afflicted infant, some critics say the tests mark another step toward allowing parents to get the perfect baby.
They say someday similar tests could perhaps even screen fetuses for personality or intelligence traits.
"It's a classic Pandora's box," said Leslie Biesecker of the National Human Genome Research Institute. "Like any powerful technology, it solves some problems while at the same time creating new ones. How you use a powerful technology decides whether it's good or bad."