Children's TV is big business, but we don't have to let big business control our children's imaginations, says Kathryn Holmquist

Children's television is big business. There are at least a dozen children's channels and more in development. The BBC will launch two new children's digital networks this year and Lego is planning to enter the market with its own digital channel. It's widely recognised within the industry that it is the marketing spin-offs that make the money.

The billion-dollar blondes - Mary-Kate and Ashley Olsen - haven't made an episode of Two of a Kind in years, yet they are making big money selling videos and fashion to "tweenagers".

But we don't have to let big business control our children's imaginations.

Parents decide whether to turn a programme on or off, or whether to spend money on spin-offs. Buying the book Walking with Dinosaurs so that children can learn more about what they have seen, or even the video series, would be a good investment. Buying every toy, yoghurt or breakfast cereal your child sees advertised on Nickelodeon would not be.

As for Teletubbies - there was a time that everyone had to have one, now who cares? Use common sense.

Children's TV has never been so good - or so terrible. Parents have the power to let their children watch the good stuff, and ignore the rest.

Science programmes broaden children's minds and their vocabularies. It's a good sign that the maker of Walking with Dinosaurs, Jana Bennett, who cut her teeth at the Discovery Channel, has just been made director of television at the BBC.

Factual programmes can stimulate children's interest in astronomy, archaeology and the arts. News documentaries can make children aware of a greater humanity around them, giving them a sense of moral responsibility for problems like pollution and homelessness.

For sensitive children, this can be disturbing, however. Research has shown that today the average child has anxiety levels that would have seen them labelled as clinically disturbed 40 years ago. What two World Wars failed to do in the 20th century, TV ultimately succeeded in: taking away the safety of childhood.

After September 11th, especially, children know that horrific, unpredictable events can happen. They may find science programmes about meteors hitting the earth far more frightening than Buffy the Vampire Slayer, because they know that while vampire aren't real, life-destroying meteors are a distinct possibility.

So just because a programme is factual or scientific, it doesn't mean that it's safe for your child to view. Care and be aware. If parents exercise control, broadcasters will eventually get the message.