Because their brains may be built that way. So says a University of Maryland School of Medicine study published in the Journal of Neuroscience, which found that young girls have a greater abundance of a protein that’s associated with language development in mammals. And this might explain why men tend to be less talkative than women.

The Maryland study measured the amount of the Foxp2 protein in the brains of rat pups. Their findings: four-day-old male rats had higher levels of Foxp2 and were more vocal than females. In a subsequent investigation, the researchers found that young girls also have higher levels of Foxp2, sometimes knows as the “language gene,” than equally aged boys.

“This study is one of the first to report a sex difference in the expression of a language-associated protein in humans or animals,” said Margaret McCarthy, PhD, one of the study’s authors. “The findings raise the possibility that sex differences in brain and behavior are more pervasive and established earlier than previously appreciated.”

As might be expected, reactions are mixed. Some observers think the study is “very exciting“; others are a bit more skeptical.

See: National Geographic