Parents trying to get their children to wear bicycle helmets -- now required by law in California for those younger than 18 -- may find helpful the advice of a UC Davis researcher. Parents should take the helmet issue seriously, because bicycles are a major cause of childhood accidental deaths, especially for boys, says Brenda Bryant, a human development and family studies professor. To set an example, parents should wear helmets when they bicycle, she says. To make helmets more palatable, parents should allow their kids to help choose their own and decorate them so they are more attractive. For teens, peer pressure is vital in prompting helmet wear, so parents may want to work through 4-H or student council leaders.