kids in wagon (IMAGE) Penn State Caption According to the researchers, so-called childhood gender role behaviors are among the largest behavioral sex differences. Typically, male adults will say they were the male character, played with other boys and preferred trucks, while female adults will say they were the female character, played with other girls and preferred dolls. Credit Patrick Mansell, Penn State Usage Restrictions non commercial use only License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.