We study how the distribution of other-regarding preferences develops with age. Based on a set of allocation choices, we classify each of 717 subjects, aged 8 to 17 years, as either egalitarian, altruistic, or spiteful. We find a strong decrease in spitefulness with increasing age. Egalitarianism becomes less frequent, and altruism much more prominent, with age. Females are more frequently classified as egalitarian than males, and less often as altruistic. By varying the allocation recipient as either an in-group or an out-group member, we also study how parochialism develops with age. Parochialism emerges significantly in the teenage years.