"Blood drawn from expectant mothers could offer parents an earlier sneak peek at their babys sex than methods currently used in the U.S. researchers said Tuesday.  The test may be particularly valuable for families that harbor sexlinked genetic disorders like hemophilia they add.  Because such disorders mostly strike boys knowing that the baby is a girl could spare the mother diagnostic procedures such as amniocentesis that carry a small risk of miscarriage.  It could reduce the number of invasive procedures that are being performed for specific genetic conditions said Dr. Diana Bianchi of Tufts University School of Medicine who worked on the new study.  But other researchers voiced concerns saying it could be misused to terminate a pregnancy if the baby isnt of the desired sex.  What you have to consider is the ethics of this said Dr. Mary Rosser an obstetrician and gynecologist at the Montefiore Medical Center in New York.  If parents are using it to determine gender and then terminate the pregnancy based on that that could be a problem she told Reuters Health. Remember gender is not a disease.  The test looks for small pieces of the male sex chromosome in the mothers blood which would mean she is carrying a baby boy. Some European hospitals already rely on the method called cellfree fetal DNA although its not available from doctors in the U.S.  What they are finding in England is that many women are not going on to have the invasive tests Bianchi told Reuters Health.  In those procedures doctors either extract a small amount of the fluid that surrounds the fetus amniocentesis or they take a sample of the placenta chorionic villus sampling. Between one in  and one in  mothers miscarry as a result according to Bianchi.  In a fresh look at the medical evidence for the blood test she and her colleagues analyzed  earlier studies that included more than  pregnancies.  They found parents could trust the test . percent of the time when it said theyd have a boy and . percent of the time when it indicated a girl.  That leaves some room for error which could be important if parents are making medical decisions based on the results  such as whether or not to get an invasive procedure to look for genetic disorders.  However the current noninvasive alternative  an ultrasound done at the end of the first trimester  isnt always good at spotting a babys sex Bianchis team reported in the Journal of the American Medical Association.  And the blood test is reliable as early as seven weeks into the pregnancy whereas ultrasound is not.  Bianchi said one study had estimated the blood test costs about  pounds in the UK about  all included. While its available over the Internet she said her team had only looked at hospitalbased test performance.  I dont know why it is not being incorporated in the US she said.  Rosser however chalked that up to the ethical issues it raises.  It is a great test that can be part of our armamentarium of noninvasive testing that we use she said. But it should only be used by families that are at risk for sexlinked diseases.  Bianchi said she owns stock in Verinata Health a company that is developing cellfree fetal DNA tests for Down syndrome although that company had no role in the new study.  The American College of Medical Genetics did not respond to requests for comment on the DNA tests.  SOURCE bit.lyHWZ httpbit.lyHWZ Journal of the American Medical Association August  .  This story has been corrected in paragraph  to show said disorders mostly strike boys not only strike boys Our StandardsThe Thomson Reuters Trust Principles. httpthomsonreuters.comenaboutustrustprinciples.html"