Explaining Boys' Language Delay

Testosterone exposure doubles risk of having impaired language

/ Author:  / Reviewed by: Joseph V. Madia, MD

(RxWiki News) Many new mothers wonder why their toddler sons don’t speak as well – or as quickly – as other children. A new Australian has an answer: Blame it on testosterone.

Researchers from the University of Western Australia studied testosterone in newborns and found that boys who are exposed to high levels of testosterone before birth are at a doubled risk of having impaired language development compared to females.

The scientists found that testosterone had the opposite effect on girls: increased levels of testosterone before birth actually lowered a girl’s risk for language delay.

"Talk with your doctor about your child’s development."

About 12% of toddlers suffer language delays, and boys are at greater risk because they develop at a slower rate, says lead author Dr. Andrew Whitehouse, a professor of psychology at the University of Western Australia, in a press release. The team’s findings give a biological explanation for this, he says.

In the study, the researchers looked at the umbilical cord blood of 767 infants and measured how much testosterone the infants were exposed to during an important phase of brain development. Then, the researchers evaluated the children’s language skills when they were 1, 2 and 3 years of age.

The team found that little boys with high levels of testosterone in the blood were 2-3 times more likely to experience language delay. The authors say that male fetuses have 10 times the levels of testosterone compared to female fetuses. They think that significantly higher levels interfere with young boys’ abilities to speak.

This study is the first large study to look at umbilical cord blood and language delay in the first three years of a child’s life.

This observational study was published in the Journal of Child Psychology and Psychiatry.

Reviewed by: 
Review Date: 
January 26, 2012
Last Updated:
January 26, 2012