Brain injury that occurs in the womb or early in a child's growth could be the root cause of autism according to new research.

A paper published just last month by Dr Samuel Wang, an associate professor of molecular biology and neuroscience at Princeton University, argues that damage to the cerebellum may contribute to autism spectrum disorders (ASDs) and other neurodevelopmental disorders later in life.

The cerebellum, Dr Wang theorizes, is responsible for helping young minds process complex sensory information, which, over time, eventually leads them to form normal social relationships.

The cerebellum only makes up about 10 percent of the brain's mass, and is mostly in charge of movement-related functions, such as coordination. Early in a child's life, however, Dr Wang makes the argument that the cerebellum has a much larger role, specifically as it pertains to social development.

"Some of the clinical and animalresearch evidence for cerebellar involvement in autism has been known for years,” Dr Wang says in an interview with The Daily Beast.

"But this evidence doesn't fit into the textbook wisdom that the cerebellum controls sensory processing and movement. At some level, researchers have been trapped by whatever framework they learned in college or graduate school."

The paper gives the example of a child's response to a parent's smile.

There is no reward to a smile, so the smile itself does not do anything to stimulate the parts of the brain that respond to rewards.

Over time however, the cerebellum begins to correlate seeing a parent smile with other rewards, such as being fed, and connects the areas of the brain that see the smile with those that signal rewards.

Should, however, a child have had any damage to the cerebellum in their formative years, they would be unable to make this connection between that part of the brain that sees the smile and that which triggers rewards, which would likely impair their social development.

Early damage to the cerebellum could also effect other "downstream" areas of the brain, such as those responsible for cognition, which would most likely inhibit normal development.

For a child known to have a cerebellar injury at birth, the paper reports an increased relative risk for an ASD as equivalent to that of a smoker developing lung cancer.