Autism, a developmental disorder that causes deficits in social behavior and communication, affects four times as many boys as girls. Because of this extreme gender imbalance, some scientists posit that sex hormones may contribute to the disease. Now researchers have identified for the first time a gene that may help explain the gender discrepancy and underlie some common autism symptoms.

In 2010 biologist Valerie Hu of the George Washington University Medical Center and her colleagues found that brains of people with autism have low levels of a protein produced by a gene called retinoic acid–related orphan receptor-alpha (RORA). Now they report in a study published in PLoS ONE on February 16 that this gene interacts with certain types of estrogen and testosterone found in the brain.