A project from the Raine Study shows testosterone levels in the womb have little impact on later childhood behavior.
The research findings have been published online in the international journal PLOS ONE.
Lead author Dr Monique Robinson said results from smaller studies had suggested high levels of testosterone may predispose children to more masculine behaviour, where low levels might predict more feminine behaviours.
"Compared to smaller studies, in this relatively large study we did not find any significant differences in behaviour as a result of differing exposure to testosterone in the womb," said Dr Robinson.
The study comprised 430 females and 429 males from the Western Australian Pregnancy Cohort (Raine) Study where umbilical cord blood had been collected. Total testosterone concentrations were determined by mass spectrometry and bioavailable testosterone (BioT) levels were calculated.
Researchers analysed bioavailable testosterone (BioT) in maternal cord blood collected at delivery and assessed the child's behaviour at age 2, 5, 8 and 10 years.
"We looked at an overall picture of the child's behaviour, as well as internalising behaviours such as anxiety or depression and externalising behaviours such as aggression or delinquency," said Dr Robinson.
"We found no effect of high or low bioavailable testosterone levels in cord blood on later child behaviour."
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About the Raine Study
The Raine Study is jointly conducted by the Telethon Institute for Child Health Research and the University of Western Australia. The study started in 1989, when 2900 pregnant women were recruited into a research study at King Edward Memorial Hospital to examine ultrasound imaging. The mothers were assessed during pregnancy and health and lifestyle information was collected on the mother and the father. After the children were born, they were assessed at birth, at one year, then two, three and five years of age. Further follow-ups of the cohort have been conducted at eight, ten, 14, 17, 20 and now 23 years of age.
Find out more about the Raine Study