In the first three years children are just gaining a sense of autonomy. In fact, in the first couple of months, they don't understand that they are a separate being from their caregiver. At each developmental milestone, (crawling, talking, walking, among others) children become more aware that they are an individual, separate from others. However, this new found sense of autonomy does not make them any less egocentric, and in fact often heightens their impulse to shout, "mine" and protect their possessions as if their life depended on it. They see the world through their own eyes and have yet to develop a sense of empathy.
In a previous post (to Share or not to Share http://www.larosaparentcoach.com/1/post/2011/08/to-share-or-not-to-share.html , I explained how this egocentricity is normal and that parents don't need to worry if their child does not want to share. Most children do not share because they are altruistic. It is more likely that they will share because they have been taught that it is socially appropriate to share by their caregivers. It is the beginning stages of learning empathy, sharing, cooperation and social skills.
Even if this research study is right - that there is a gene that predicts altruism/selfishness - It is unlikely that it will prevent a child from developing into a generous person. A child may be more or less likely to become an altruistic adult based on a gene, but there are many other factors that play a role. Modeling and teaching cooperation, empathy and sharing will increase the likelihood (gene or no gene) that your child will develop into an empathic, generous and altruistic person.
Click here to read the Wall Street Journal Article referenced: http://online.wsj.com/article/SB10001424052970204450804576623162047263634.html