Cooler but still well above normal this week

MPR News helps you turn down the noise and build shared understanding. Turn up your support for this public resource and keep trusted journalism accessible to all. 

Turn Up Your Support


      CHICAGO - Boy or girl? A simple blood test in mothers-to-be
can answer that question with surprising accuracy at about seven
weeks, a research analysis has found.


      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.


      They 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 authors say the results suggest blood tests like those
studied could be a breakthrough for women at risk of having babies
with certain diseases, who could avoid invasive procedures if they
learned their fetus was a gender not affected by those illnesses.
But the study raises concerns about couples using such tests for
gender selection and abortion.


      Couples who buy tests from marketers should be questioned about
how they plan to use the results, the study authors said.


      The analyzed test can detect fetal DNA in mothers' blood. It's
about 95 percent accurate at identifying gender when women are at
least seven weeks' pregnant - more than one month before
conventional methods. Accuracy of the testing increases as
pregnancy advances, the researchers concluded.


      Conventional procedures, typically done for medical reasons, can
detect gender starting at about 10 weeks.


      The new analysis, published in Wednesday's Journal of the
American Medical Association, involved more than 6,000 pregnancies.


The testing used a lab procedure called PCR that detects genetic
material - in this case, the male Y chromosome. If present in the
mother's blood, she's carrying a boy, but if absent, it's a girl.


      Tests that companies sell directly to consumers were not
examined in the analysis. Sex-detection tests using mothers' urine
or blood before seven weeks of pregnancy were not accurate, the
researchers said.


      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.


      Simpson noted that using gender-detection blood testing for
medical or other reasons has not been endorsed by guideline-setting
medical groups and some experts consider it experimental.


      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.


      Recent research found that increasing numbers of women in India
who already have daughters are having abortions when prenatal tests
show another girl, suggesting that an Indian ban on such gender
testing has been ineffective. The expense of marrying off girls has
contributed to a cultural preference there for boys.


      Evidence also suggests that China's limits on one child per
couple and traditional preference for male heirs has contributed to
abortions and an increasingly large gender imbalance.


      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.


      Consumer Genetics Inc. a Santa Clara, Calif.-based company sells
an "early gender" blood test called "Pink or Blue" online for
$25 plus $265 or more for laboratory testing. It boasts of 95
percent accuracy, using a lab technique its scientists developed
from the type of testing evaluated in the new analysis, said Terry
Carmichael, the company's executive vice president.


      Carmichael said the company sells more than 1,000 kits a year.
He said the company won't test blood samples unless women sign a
consent form agreeing not to use the results for gender selection.


      The company also won't sell kits to customers in China or India
because of fears of gender selection, he said.


      Medical techniques that can detect gender include amniocentesis,
usually done at around 16 weeks, using a needle to withdraw fluid
surrounding the fetus to identify abnormalities; chorionic villus
sampling, done at around the 10th week to detect abnormalities by
examining placenta tissue; and ultrasound, most accurate at around
13 weeks. The first two methods can slightly increase risks for
miscarriages.


      JAMA: http://www.jama.ama-assn.org

Gallery

Health

Boy or girl? A simple blood test in mothers-to-be
can answer that question raises concerns.

Boy or girl? A simple test raises ethical concerns

Go Deeper.

Like this?

News you can use in your inbox