Whoever told you that obviously doesn't know much about metal and behavioral problems. A television program of any type can NOT cause ADHD. I'm now a stay at home mom, but I use to be a social worker and worked specifically with children who had ADHD and autism. I agree that you can't prop you baby in front of the TV all day, but you can use it as some fun time between you and your baby or even to get the dishes washed, laundry folded or what not. My son, who is now 21 months LOVES baby Einstein and he is developmentally fine.
If you are worried about ADHD, look at your family history and do your research. I found that a lot of the kids I worked with were getting way too much sugar (juice, candy, soda) and not enough exercise or sleep. Just keep that in mind.