If it seems to be taking your baby boy a long time to say his first words, blame testosterone. A new study shows boys exposed to elevated levels of the male hormone while in utero have more than twice the risk of language delays compared to girls.

The Australian study used the umbilical cord blood of 767 newborns to measure how much testosterone the infants were exposed to during a critical phase of brain development. Language ability was then measured when those kids were 1, 2 and 3 years old.

Researchers’ results showed that while baby boys with high testosterone levels were two to three times more likely to have a language delay than females, girls exposed to those same elevated testosterone levels didn’t have similar problems — in fact, they had a lower risk of them.

The researchers noted the greater likelihood of language delays may be because male fetuses have 10 times the levels of testosterone than females.

“An estimated 12 percent of toddlers experience significant delays in their language development,” said study lead author Professor Andrew Whitehouse at the University of Western Australia. “While language development varies between individuals, males tend to develop later and at a slower rate than females.”

In a journal news release, he added, “Language delay is one of the most common reasons children are taken to a pediatrician. Now these findings can help us to understand the biological mechanisms that may underpin language delay, as well as language development more generally.”

While the study, which appears in the Jan. 26 issue of the Journal of Child Psychology and Psychiatry, found an association between testosterone levels and language delays, it did not prove a cause and effect.