Will is affected by his chromosones.

Indeed, I have seen it time and again. Possesing a "Y" chromosone automatically means that there will be an affinity for cars. It's a given. We have toys that are meant for girls and toys that are typically those of the boys domain. Boys like cars and trucks. No matter what other offerings they have in the toy department, the "y" chromosone is a car magnet. If a car is not available, anything that can be pushed or dragged will do when accompanied by the requisite brrr brrr noise. Even with the addition of a whole extra chromosone does not hinder the mighty "Y". So here is Will celebrating his boyhood in it's most typically predestined fashion.

Fun With Cars