Investigating the Prenatal Testing Market

For more information on today's episode, visit nytimes.com/thedaily. About a decade ago, companies began offering pregnant women tests that promised to detect rare genetic disorders in their fetuses. The tests initially looked for Down syndrome and worked well, but later tests for rarer conditions did not. An investigation has found that the grave predictions made by those newer tests are usually incorrect. We look at why the tests are so wrong and what can be done about it.