Once they know which camp they belong to, their sense of self quickly becomes tinted pink or blue and they begin to infer how to fit in. That's why around age 3, a child's behavior is likely to become noticeably gender-specific. Toddlers aren't able to consider exceptions to the rules they perceive. As with learning anything, they need to get the basics right before trying variations. In time, they'll be more willing to step outside the boundaries.
Parents can help by making kids feel good about the differences between boys and girls.
Model the behavior you want your child to learn. If stifling sex-related stereotypes is important to you, make sure he sees Mom mowing and Dad dusting. Offer gender-neutral toys, but be aware that your influence may be slight. Toddlers are learning as much from their peers' behavior as from their parents'. In the meantime, expect your child to stick close to gender roles until about age 8 to 10.