I think that's a start. I think that as a broader culture though, that child is going to be socialized and acclimatized to what kind of gender role is expected of them when they go to day care, and when they go to school later on. Keeping magazines out of the house and turning off the TV set is great, but children are going to encounter these values as soon as they enter public school and other spaces where they meet up with other children.
Children themselves learn what kind of gender identity is expected of somebody, of them as a girl or as a boy, and they learn how to perform that because they want to fit into the social order, the social world. So we have to be thinking about prevention in a much broader way, not just targeting individual families.