Should schools start later in the morning?

In today’s busy life schedule for teenagers, the first activity when their day starts is to abandon sleep. However, researches show that the sleep deficit of teenagers today is encumbering high school students' achievement. Indeed, no one does well when they’re sleep-deprived, but insufficient sleep among children has been associated to obesity and to learning issues like attention deficit/hyperactivity disorder etc.
According to various surveys and research, teenagers’ body clocks are set to a schedule that is different from that of younger children or adults. This prevents adolescents from nodding off until around 11p.m., when they produce the sleep-inducing hormone melatonin and rising up much before 8 a.m. when their bodies stop producing melatonin. The result is that the first class of the morning is often a waste, which contributes to failure and dropout rates.
It is a fact that every morning in a school environment, we see a decent number of teens who have that "I don't want to be here, I just want to sleep" look on their faces. Yet in the afternoon, right when school ends, they act like they're on ten cups of coffee. This is because their day starts way too early. Even for getting ready for school they have to rise way before time, sufficient enough for them to get ready, have breakfast and to cover the kilometers to the school campus.
Of course, when school starts later, it has to end later. But instead of taking this as a liability, we should see it as an opportunity to extend the day; it would help working parents if their children were on the same schedule. Parents are likely to have ample time in the evening to spend with the child. This will allow the child to grow up in a healthier environment where the parents are physically present more often.
If schools start later, this can have a positive influence on the students. It can give students more time to sleep, they will be fresh and alert for their educational tasks at school, contributing to improved grades. This will generate more enthusiasm and give more motivation to a student.