It used to be that pregnancy gurus (a.k.a. grandmas at a baby shower) would analyze how high the mother's pregnant belly was to guess if it were a boy or girl, or they would take a ring on a string and see which way it spun. New research shows that a simple blood test can answer this question with surprising accuracy at about seven weeks.
Though not widely offered by U.S. doctors, gender-detecting blood tests have been sold online to consumers for the past few years. Their promises of early and accurate results prompted genetics researchers to take a closer look.
Researchers analyzed 57 published studies of gender testing done in rigorous research or academic settings — though not necessarily the same methods or conditions used by direct-to-consumer firms.
The results suggest blood tests could be a breakthrough for women at risk of having babies with certain diseases. But the study also raises concerns about couples using such tests for gender selection and abortion.
Fox News reports that medical specialists have split opinions on the issue when it comes to the ethical uses of the test as well as its accuracy due to the variability of testing conditions:
Senior author Dr. Diana Bianchi, a reproductive geneticist and executive director of the Mother Infant Research Institute at Tufts Medical Center in Boston, called the results impressive. She noted that doctors in Great Britain are already using such testing for couples at risk of having children with hemophilia or other sex-linked diseases, partly to help guide treatment decisions.
The research indicates that many laboratories have had success with the test, but the results can't be generalized to all labs because testing conditions can vary substantially, said Dr. Joe Leigh Simpson, a genetics professor at Florida International University. He was not involved in the study.
Dr. Lee Shulman, chief of clinical genetics at Northwestern Memorial Hospital in Chicago, said the testing "isn't ready for prime time."
He said his hospital doesn't provide the blood tests, and doesn't offer more conventional techniques, including amniocentesis, to women who have no medical reason for wanting to know their baby's gender.
"I would have a lot of difficulties offering such a test just for gender identification. Gender is not an abnormality," Shulman said. "My concern is this is ultimately going to be available in malls or shopping centers," similar to companies offering "cute" prenatal ultrasound images.
Fox News also reports that gender tests could be increasing the number of abortions in countries like India and China where having a girl is not preferable. In the United States reasons for abortions remain unclear:
There's very little data on reasons for U.S. abortions or whether gender preferences or gender-detection methods play a role, said Susannah Baruch, a policy consultant for the Generations Ahead, an advocacy group that studies genetic techniques and gender issues.
The study, published in the latest issue of the Journal of the American Medical Association, was conducted with researchers using PCR to detect Y chromosome sequences and testing was most accurate after 20 weeks of gestation. Testing for gender before seven weeks was not accurate. Testing the mother's blood for traces of fetal DNA could be an alternative to more invasive gender testing procedures like amniocentesis and chorionic villus sampling.
The Associated Press contributed to this report.