A new study has found that males are biologically programmed to be drawn to balls, vehicles and construction toys.
According to scientists from Texas Aand M University, hormones released both before birth and well into the first few months of life may dictate the type of toys and play that boys are drawn to.
The research team hints that exposure to differing levels of hormones in the uterus might influence the preferences that both boys and girls have for "boy-like" toys later on.
During the study, lead researcher Gerianne Alexander used eye-tracking software to measure levels of interest in animations of a ball versus a doll and a group of figures versus an individual figure, in 21 boys and 20 girls aged 3 to 4 months.
The team measured levels of oestrogen in the girls' saliva and testosterone in the boys' and compared the lengths of their index and middle fingers - a guide to prenatal testosterone exposure.
They found that boys exposed to more prenatal testosterone showed a pronounced preference for the ball.
However, girls' behaviour appeared unaffected by current or prenatal hormone levels.
Those with higher circulating levels of testosterone had a stronger preference for the groups of figures over the individuals, while those whose finger lengths indicated that they had been exposed to more testosterone in the uterus showed a more pronounced preference for the bouncing ball over the doll "It's a very interesting paper and I think it will motivate a lot of additional research," New Scientist quoted Melissa Hines of the University of Cambridge, who researches the role of hormones in prenatal development, as saying.
The study appears in journal Hormones and Behaviour.