M.D.
I'll be honest, I let my kids watch TV before they were 2, I usually have it going too when we are at home, it only shuts off when it's time to go to bed or we leave the house. My oldest is 16, then 14 and I have an almost 5 year old. My older two children are straight A's, honor students, my son 14 year old is very athletic, but does love to watch TV. My daughter is thick like me, so in that since TV isn't great for her. However, this is the same child at age 4 when going trick-or-treating after walking one block told me she had enough candy. So being physical hasn't never been top on her list. I have even seen how TV has been positive for them. They went outside to play when they were younger and did other things, but I don't see where TV was so bad for them.
Again, this is my opinion, I'm not a doctor, but I am a proud mother, who has very successful children and even their teachers have said they wish they had a classroom filled with children like them.