In a first since the 1980s, rates of twin births in the US are dropping

A recent report by the Centers for Disease Control and Prevention shows that the twin birthrate has dropped in the United States after rising for more than 30 years. Experts say it could have something to do with improvements in assisted reproductive technology. The decline affected mothers over the age of 40, and non-Hispanic white mothers, while the rate of twin births among non-Hispanic black and Hispanic mothers was essentially unchanged.