Stanford adolescent medicine expert Bonnie Halpern-Felsher, PhD, is worried that flavored vape and e-cigarette products are a gateway to nicotine use for young people. "So far, all the research on adolescents and young adults is showing that today's youth are not starting with cigarettes," she told me recently. "Young people just have very negative opinions of cigarettes and no intentions of using them. But they have more favorable perceptions of e-cigarettes."