According to the USA Swimming Foundation, about 70 percent of African-American children, 60 percent of Latino children and 40 percent of white children are non-swimmers. Lack of access and financial constraints account only partly for these numbers. Fear, cultural factors and even cosmetic issues play a role as well.

"Before the Civil War, more blacks than whites could swim," Lynn Sherr, the author of Swim: Why We Love the Water, said in an interview. "There are many stories of shipwrecks in which black slaves rescued their owners."

But as Ms. Sherr learned from Bruce Wigo of the International Swimming Hall of Fame, segregation destroyed the aquatic culture of the black community. "Once whites discovered swimming, blacks were increasingly excluded from public pools and lifeguarded beaches," Mr. Wigo told her.

As a result, many minority parents never learned how to swim. Adults who can't swim often fear the water and, directly or indirectly, convey that fear to their children.