You hit the snooze button one too many times and now there’s no way you’ll be on time for first period. As you dash out the door, hoping your teacher will let you in, you sigh, “If only school started later.” Most high schools in the U.S. start at 8 a.m. or earlier, but many pediatricians believe schools should start later. Advocates say later start times would allow teens to sleep more, which would benefit their health and academic performance. And some states, like California, have already implemented 8:30 a.m. start times. But opponents worry that since later start times will mean later dismissals, students may not get home until well after dark. What do you think?