NEW YORK: Blood drawn from expectant mothers could offer parents an earlier sneak peek at their baby's sex than methods currently used in the US, researchers said Tuesday.
The test may be particularly valuable for families that harbor sex-linked 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 isn't 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 mother's blood, which would mean she is carrying a baby boy. Some European hospitals already rely on the method, called cell-free fetal DNA, although it's not available from doctors in the US.
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 100 and one in 600 mothers miscarry as a result, according to Bianchi.
And the blood test is reliable as early as seven weeks into the pregnancy, whereas ultrasound is not.
"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 sex-linked diseases."