(This is an excerpt of the Health Rounds newsletter, where we present latest medical studies on Tuesdays and Thursdays.)

By Nancy Lapid

(Reuters) -The age of the father plays a role in pregnancy outcomes, with harmful genetic changes in sperm being substantially more common in older men, new research shows.

Along with a steady build-up of random changes in DNA as men got older, the researchers also discovered the increase in mutations is due to a subtle form of natural selection, with some mutations having a competitive edge during sperm production in the testes, according to a report in Nature.

In 81 healthy volunteers, researchers found that approximately 2% of sperm from men in their early 30s carried disease-causing mutations, compared to 3% to 5% of sperm from men ages 43 to 74, a

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