Genetic screening cuts cases of inherited diseases

Some of mankind's most devastating inherited diseases appear to be declining, and a few have nearly disappeared, because more people are using genetic testing to decide whether to have children.

Births of babies with cystic fibrosis, Tay-Sachs and other less-familiar disorders have dropped since testing came into wider use, The Associated Press found from a review of studies and interviews with numerous geneticists and other experts.

Many of these diseases are little-known and few statistics are kept. But their effects, ranging from blood disorders to muscle decline, can be disabling and often fatal during childhood.

Now, more women are being tested as part of routine prenatal care, and many end pregnancies when diseases are found. One study in California found that prenatal screening reduced by half the number of babies born with the severest form of cystic fibrosis because many parents chose abortion.

More couples with no family history of inherited diseases are getting tested before starting families to see whether they carry mutations that put a baby at risk. And a growing number are screening embryos and using only those without problem genes.

The cost of testing is falling, and the number of companies offering it is rising. A 2008 federal law banning gene-based discrimination by insurers and employers has eased fears.

Genetic testing pushes hot-button issues: abortion, embryo destruction and worries about eugenics - selective breeding to rid a population of unwanted traits. Yet it is touching a growing number of people.

For example, in Vancouver, Canada, Jeff and Megan Carroll screened embryos to have two children free of the Huntington's disease gene Jeff has. Huntington's is a progressive, fatal neurological disorder. "I felt very strongly that I didn't want to pass on this," he said. Huntington's "is done killing people in my family when I am gone."