How much do you want to know about your unborn child's DNA?S

Over at Wired, there's a fantastic article about the rise of prenatal genetic testing. Erin Biba explores how the ability to test for common genetic abnormalities is changing life for many parents — and touches on how the world could be changed, now that we have a non-invasive, easy method of testing an unborn baby's genetic makeup. Most people would like to know if their unborn child is likely to have certain severe conditions, or ones that can be treated easily, but are there things you're better off not knowing about your baby?

Top image: Stephen Coburn/Shutterstock.com

Biba's piece begins:

Candace Weiss didn't know she had a family history of birth defects until she got pregnant with her daughter. That's when she learned that her grandmother, at the age of 42, had given birth to a baby with Down syndrome. "That child died young," she says. "But back in that time, they sent them away. She wasn't even raised in the family."

Weiss' own child was born perfectly healthy. Not long after, she and her husband started trying for a second baby. But she had a miscarriage. And then another. The second miscarriage was the result of triploid syndrome-the fetus had three of every chromosome instead of the normal two. So when Weiss, a 32-year-old lawyer turned stay-at-home mom in Westchester, New York (her name has been changed for this story), got pregnant again, her doctors watched her closely. "We did a lot of ultrasounds," she says. "Everything looked like it was going well."

Many women with high-risk pregnancies (which also includes women over 35) elect to undergo amniocentesis or chorionic villus sampling-invasive procedures that check for chromosomal abnormalities but carry with them a risk of miscarriage. Weiss says there was "no way in hell" she was going to do that. She didn't want to risk losing another baby. Well, said her doctor at her 10-week office visit, we've got this new test that checks for the most common chromosomal disorders (like Down syndrome). All it requires is a blood draw. And you can do it right now. The test was so new, in fact, that Weiss was one of the first patients in her doctor's practice to have it.

A week or so later the doctor called. The baby had Down syndrome. "We were obviously shocked," Weiss says. "Even the doctor was shocked." Weiss then had a chorionic villus sampling performed, on the remote chance of a false positive. It confirmed the blood test result, but she and her husband were already resigned to what was to follow. She says she needed to talk through the decision to end the pregnancy, but her husband never had any doubt. "His coping mechanism was just to be done with it," Weiss says. But for her, it was a bit different. "You hear this news and you make your decision. But meanwhile you're still pregnant. I mean, I was still nauseous."

Weiss terminated the pregnancy last fall at 12 and a half weeks. She and her husband hadn't told very many people that she was pregnant, and the procedure at that stage is mercifully swift and relatively simple. Some women do not find out their babies have serious medical problems until much later in their pregnancies. At that point, many doctors don't even perform abortions, obliging patients to travel to distant cities to get one. "It's huge to know early on," Weiss says. "Not that what we went through wasn't heartbreaking, but we were able to put it behind us faster. We get to start over sooner."

Before she knew about the blood test, Weiss-like hundreds of thousands of pregnant women each year-had been facing a complicated decision: Risk a perfectly healthy pregnancy to find out for sure if there's something wrong with your child, or live with a degree of uncertainty. It's a trade-off inherent in prenatal tests. Some are accurate-they can say for sure whether a child has a serious disorder-but may cause side effects; others are safer but give a more ambiguous level of information-all you get is the odds of whether or not the child has problems.

Read the rest over at Wired.