Blood tests are now available to reliably determine paternity as early as the eighth or ninth week of pregnancy, The New York Times reported.
While invasive procedures such as amniocentesis or chorionic villus sampling (CVS), performed between 10 and 20 weeks, can also determine paternity, the new tests -- requiring only blood samples from the pregnant woman and the potential father -- carry less risk of miscarriage.
And while noninvasive paternity tests have been offered over the Internet for about a decade, experts say technology has advanced to the point that such testing can now be done reliably.
The tests analyze fragments of DNA from the fetus present in the mother’s blood.
"I have no doubt that these tests will work clinically," said Mark I. Evans, a professor at the Mount Sinai School of Medicine and director of Comprehensive Genetics, told the Times.
A paper describing one such test, developed by a company called Ravgen, was published last month in the New England Journal of Medicine.
Meanwhile, genetic researchers at the University of Washington had sequenced nearly the entire genome of an 18-week-old fetus using only a sample of the mother's blood and a swab of the father's saliva.
According to a separate report in The New York Times, scientists discovered in the 1990s that about 13 percent of the DNA floating freely in a pregnant woman's blood, outside her cells, belonged to her fetus. Further, the fetus gets half its DNA from the mother and half from the father.
Taking the genetic testing a step further, early and noninvasive prenatal testing for a number of genetic disorders could be a real possibility very soon, according to www.Care2.com.
However, as the website pointed out that as the cost of analyzing fetus DNA -- currently about $20,000 to $50,000 -- fell, and as a result possibly became widely available in three to five years, the ethical implications mounted.
For example, about 85 percent of expecting American parents who learned their fetus had Down Syndrome choose to abort.
The cost of blood testing for paternity meantime, was now as low as $950 to $1,650, offered by Ravgen, the Columbia, Maryland based company's chief executive Dr. Ravinder Dhallan told the Times.
That's compared with around $500 for a conventional postbirth paternity test.
Another test developed by Silicon Valley company Natera was priced at $1,775, The Times wrote, adding that thousands of the prenatal tests had been ordered since it went on sale last August.