Here's a look at some of the top health news being talked about around the U.S. and the world today:

• Researchers believe a later start time for schools might help reduce teen car crashes, according to a new study looking at two Virginia cities. Reported in the Los Angeles Times blog, the study found a lower incidence of crashes among teens who had a later school start time. The study was presented this week at the annual meeting of the Associated Professional Sleep Societies in San Antonio.

• Researchers say they're on to the genetic background of autism. They have found genetic abnormalities that are "unusually prevalent" in those who have the disorder, it was reported on Business Week.

• In the same way doctors might advise a patient to stop smoking, they should tell patients not to text or talk on the cell phone while driving, a physician wrote in the New England Journal of Medicine. Reported by Reuters, doctors are pushing to recognize and target the behavior as one that's harmful to their patient's health and should be curbed.

Tina Reed covers health and the environment for AnnArbor.com. You can reach her at tinareed@annarbor.com, call her at 734-623-2535 or find her on Twitter @TreedinAA.