The number of American babies born with Down syndrome is on the decline despite a dramatic increase in the number of babies who are diagnosed prenatally with the chromosomal disorder, researchers say.

The reason: women are having children later in life leading to higher incidents of the developmental disability. But with an increasing number of babies being tested for Down syndrome prenatally and 92 percent of parents choosing to terminate pregnancies when the disorder is discovered, 15 percent fewer babies with Down syndrome are born.

The trend in the United States closely mirrors research released in October in the United Kingdom, which found that Down syndrome births in that country remain steady even though diagnoses are up by 71 percent.

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Currently about 400,000 Americans have Down syndrome. Advocates worry that a decreasing number of children born with the disorder will lead to reduced research and funding, reports ABC News. To read more click here.