Most teenagers aren’t morning people. Plenty of families know this from experience, but science also backs it up. The brain changes during puberty, causing most teens to stay awake later at night. Pair that with early morning school start times, and most teens can’t get the sleep they need for optimal physical health, mental health, driver safety and academic performance.

When schools start too early, many teens are prevented from obtaining both the quality and quantity of sleep they need. Early morning sleep is more valuable for teen brains and bodies than late night sleep, so the idea that “teens just need to go to bed earlier” does not match the science.

It’s not just that they might be grumpy — it’s that the risks associated with sleep deprivation are serious. They include increased rates of illness, suicide, depression and car accidents. A recent study from Rutgers University-Camden showed that early school start times are even linked to delinquency and substance abuse issues among teens.

Unfortunately, school schedules in California haven’t kept up with advancements in the science of the teenage brain.

Across the country, more and more school districts are implementing later school start times for teenagers, with positive results, but in California, 80% of middle and high schools still start too early for the sleep needs of adolescents.

California now has the opportunity to change that. SB328, currently sitting on Gov. Gavin Newsom’s desk, would limit how early secondary schools can require attendance: no earlier than 8 a.m. for middle school and 8:30 a.m. for high school. Optional before-school “zero periods” are allowed under the legislation, and rural districts are exempt from the rules.

Newsom should do what’s best for children and sign this into law.

This bill is based on recommendations from the American Academy of Pediatrics and backed by an overwhelming amount of research and medical consensus.

In fact, a letter from more than 120 leading experts in public health, medicine, safety and sleep was recently sent to Newsom urging him to sign SB328.

“The volume, breadth, consistency, and strength of the peer-reviewed scientific research supporting this legislation are unequivocal, and they exceed the high standards for public health and education policy,” they wrote.

The bill is co-sponsored by the California State PTA, which has over 700,000 members. For parents, this bill is about protecting the health and safety of their children, and supporting their academic success. It’s a simple question for them: What’s best for our children?

Of course, millions of teenagers would be on the side of those experts. They’ll be happier and healthier and will do better in school. All of California’s children should be protected from health and safety risks. They deserve to have a public education system with a school start time that doesn’t cause them harm.

Policy solutions to some of California’s problems are murky and difficult. This is not one of them.

The solution to the crisis of adolescent sleep deprivation is clear and straightforward: Do what’s best for students by starting school later.

Carol Kocivar is a past president and legislative advocate for the California State PTA. Her two children graduated from San Francisco public schools.