The spread of the new coronavirus is shining a spotlight on a little-discussed gender split: Men wash their hands after using the bathroom less than women, research and observations show.

Health officials advise that regular hand-washing is one of the best weapons against the virus.

The U.S. Centers for Disease Control and Prevention's online fact sheet "Handwashing: A corporate activity" cites a 2009 study that finds "only 31 percent of men and 65 percent of women washed their hands" after using a public restroom.