Psychologist Dr Aric Sigman has listed 15 health problems that previous studies have attributed to excessive TV viewing by children. The study covers "screen time", which includes games consoles and computers as well as TVs. It looked at the volume of screen time - but not the content.
This is something which all parents wrestle with. All parents think they have got the balance right but studies such as this concentrate the mind. It is a question of balancing screen viewing with other activities.
I would also say that anyone who has tried to find just 30 minutes of time to do a few chores uninterrupted by a small child, is grateful for any respite which a telly can provide. Anyone who doesn't welcome such a respite as a godsend, hasn't looked after a small child.
I would also praise the BBC for their children's programming. Although CBBC can tend towards wall-to-wall Basil Brush and Chucklevision at times, it is generally sensible and reasonably educational television.