Researchers in Australia have uncovered further evidence of a link between testosterone and autism, backing a theory that high testosterone exposure in the womb increases the risk of the disorder, The Australian reported Monday.

Researchers at the Telethon Institute for Child Health Research in Perth, Western Australia, found that girls with autistic-like behaviors at 2 years old had their first period about six months later than girls without the disorder's symptoms.

"These findings indicate that exposure to testosterone in the womb may be regulating both autism-like behaviors and the age of first period and that this may play a role in clinical autism," lead researcher Andrew Whitehouse said.

He said the findings were linked to the so-called "male brain theory" of autism, which suggests the behavior disorder is an extreme form of male mental traits.

"Autism is a real male-dominated condition; it affects around four males to one female, but there are also characteristics of people with autism that are more male-like," he said. "People have started thinking what might cause that, and the obvious candidate is male-type hormones and the most biologically active is testosterone."

The study looked at 383 girls who had no diagnosis of autism. At 2 years old they were each given a rating for showing autistic-like behaviors such as avoiding looking people in the eye.

Whitehouse and his team are now embarking on a world-first study to further examine the link. In utero testosterone levels will be tested in pregnant women who already have an autistic child.

The levels will be compared with a control group of pregnant women who do not have a history of autistic children.

Click here to read more from The Australian.