Exposure to high levels of testosterone before birth may increase the risk of delays in language development for boys, a new study from Australia suggests.
The findings suggest one reason why boys are more susceptible than girls to language delay, according to the researchers.
"For many years, the possible causes of language delay have been a mystery," said lead author Andrew Whitehouse, a psychologist at the University of Western Australia. "This finding may enable us to identify early on if a child is at increased risk for language delay,so we can take steps to promote their language development from the earliest stages of life."
The findings were published today (Jan. 25) in the Journal of Child Psychology and Psychiatry.
Girls develop language skills faster than boys
The pace in developing language skills can vary greatly from child to child, but previous research has shown girls generally outpace boys.
One study found that 12 percent of children experience a significant delay in language development, and that most of them are male.
But Mabel Rice, a speech pathologist at the University of Kansas, said most boys catch up to girls by the time they reach school age. "Most of them can overcome this," said Rice, who was not involved with the study.
Boys and girls may process testosterone differently
In the new study, researchers measured testosterone levels in the umbilical cord blood of newborns, then examined the children's language abilities at 1, 2 and 3 years of age. Parents also completed questionnaires about their children's development.
Researchers found male infants with high levels of testosterone in the blood were two to three times more likely than girls to experience language delays. The opposite effect was found in female infants: High levels of testosterone in the blood were associated with a decreased risk of language delay.
Whitehouse said this may be due to differences in the way males and females process testosterone.
It also may be that testosterone influences other areas of development, which in turn affect language development, Rice noted.
When it comes to language delays, Rice recommended that parents pay close attention to their child's vocabulary.
"By 2 years of age, their child should have about 50 words in their vocabulary," she said. "If they don't, they might want to consider taking their child to see a pediatrician or specialist."
Pass it on: Testosterone levels might influence baby boys' language development.