Baby boys like to play with dolls more than cars or trucks, a study by University of Western Sydney reveals.

The study results have contradicted the general belief that boys like playing with 'macho' toys.

For the study, the researchers examined the choices of babies aged from four to five months.

The researchers showed the babies photos of male and female human dolls along with pictures of cars and stoves. After this, the researchers calculated the time the babies took to stare at the photos. The authors then measured the preferences of the babies by analyzing the time taken by them to see each photo.

The observations showed that baby boys gazed at the dolls more than they looked at the trucks and cars.

"As surprising as it may sound, although the thing to do is to buy dolls for girls and cars for boys, the science suggests boys actually prefer dolls," lead study author Dr Paola Escudero said in a press release.

"Everyone loves buying dolls for baby girls and cars and trucks for baby boys, it's simply what we do. This common knowledge is supported by previous studies finding that 3-year-old boys prefer to play with transportation and construction toys whereas girls prefer to play with dolls," said Escudero.

But, the study did not find any gender-specific preferences when the babies were five months. This means that the changes happen due physiological reasons (eg their hormone levels), cognitive development or social pressure.

The research team said that further research is required to understand the reason behind gender-specific choices older children make.

"More research is needed to fill in the gap between five months and three years to determine if it's nature or nurture that triggers little boys' interest in toy cars and trucks and other stereotypically male-associated toys," she said.

The study was published in the Journal of Experimental Child Psychology.