My three children fight for their sleep. They refuse to climb out of bed and search for pants, socks and uniform shirts, to put their lunches in their backpacks, to pack a book for the 45-minute bus ride. They are not sick, but they are tired. Tired of this routine, as thousands of children -- and their parents -- in the Boston public school system are.

The iPhone trills. It’s 5:15 am. Maybe my children will drink in those last 15 minutes before their official wake time. Or maybe the whole house will be startled awake by the alarm or the dog or the toilet’s flush. If so, that will be 15 precious minutes, lost.

In Boston, the history and unintended consequences of segregated schools haunt both the city and the schools in surprising ways, like stealing children’s sleep. Busing became the key to desegregation, and for more than 40 years, children have traversed this sprawling, historic city in long yellow buses built for streets much wider than ours. The city’s ensuing traffic issues led to staggered start times in public schools, ranging from 7:15 to 9:20 a.m.

With calls to shrink the sprawling zones that determined school choice, as well as pressure to reduce busing costs, the Boston Public Schools (BPS) developed a kindergarten through sixth-grade “home-based school choice” assignment process in 2013 that uses an algorithm developed by an MIT student. This system aims to limit the distance children travel to schools, but if they are expected to have pencil in hand by 7:15, children are rising early no matter how long their commute.

Here’s the problem with denying children the sleep they need: They don’t learn as well when they are tired. Grades are not the only thing to suffer -- students experience anxiety, depression, poor concentration and behavioral problems. What’s more, the latest research on teenagers’ sleep patterns suggests that, as puberty begins, their circadian rhythms shift to a “sleep phase delay,” which means they naturally fall asleep as late as 10:00 and 11:00 at night, even as their need for up to nine hours of sleep remains the same.

Deborah J. Bennett: "Grades are not the only thing to suffer—students experience anxiety, depression, poor concentration and behavioral problems."(Lily Monster/Flickr)

So consider the next step in the BPS schooling ladder: high school. For students who hope to attend one of the city’s three sought-after exam schools, there is no home-based placement algorithm. The start times for these schools, scattered across the city, are all before 8:00 in the morning. That means that thousands of teens who live nowhere near their school rise as early as 5:30 in the morning in order to get to school on time. Our neighbors’ kids barely have time to grab a cereal bar on their way out the door before they board one or more MBTA buses to get to school, where they toss their backpacks and lunch in a locker before racing to Algebra at 7:20.

While parents at one exam school in Boston tried, unsuccessfully, to have their start time changed, parents and school administrators from middle class suburban districts outside of Boston are having more success in doing so. Which leads us to a compelling piece of research that suggests that there is a class and racial divide when it comes to sleep. As one article puts it, “sleep has its own caste system.”