The American Academy of Pediatrics discourages television watching in children under 2 years old. Watching TV before the age of 2 increases the chance the child will be diagnosed with ADHD. Watching TV impacts the way children's brains develop. It is especially important for very young children to play as it teaches them about the world and wires their brain appropriately.
More info:
American Academy of Pediatrics' Healthy Children website for parents and article on television
article: it's official: tv linked to attention deficit
Study in Pediatrics: Early Television Exposure and Subsequent Attentional Problems in Children
