Boys exposed to high levels of testosterone in the fetal stage are twice as likely to experience delays in language development, according to researchers at Perth's Telethon Institute for Child Health Research, Australia.
Lead author of the study, Prof. Andrew Whitehouse said, "While language development varies between individuals, boys tend to develop later and at a slower rate than girls. An estimated 12 percent of toddlers experience significant delays in their language development."
The research team measured testosterone levels in the umbilical cord blood of 767 newborns before examining their language ability at 1, 2 and 3 years. It was seen that boys with high levels of testosterone in cord blood were between two-to-three times more likely to experience retarded language development. However, the opposite was found in girls where high-levels of testosterone in cord blood were associated with a decreased risk of language delay.
The finding is significant as it gives a biological explanation for why boys' language development differs to that of girls. Dr. Whitehouse said, "Language delay is one of the most common reasons children are taken to a pediatrician. Potentially, this could help us to identify children at higher risk for language delay at an earlier age, increasing the opportunity for effective therapies."
The research has been published in the 'Journal of Child Psychology and Psychiatry'.