Television in a child's bedroom?

There are a few questions I'm expecting as my boys get older. Can I have a bigger allowance? Can I have some (insert popular-brand-name here) shoes/shirts? Can I stay out later, ride my bike further, "study" with a girl up in my room, (gulp) drive my car on the interstate? Etc. 

I got one of them last night from my 10-year-old son: "Mom, can I get a TV in my room?"

Luckily my husband and I had talked about this before and have decided our answer is no way. "Why not? I wouldn't watch anything bad," my son asked, and then went on to name two friends who have TVs in their rooms. I imagine more of his friends will score a TV over the years and the pressure on us will increase. But we're not caving. Same goes for computers, he'll soon learn to his dismay.

As I found out from a quick Web search today, I have research on my side. Kids who have televisions in their rooms are more likely to score lower on school achievement tests, have problems sleeping and read less often, numerous studies have shown. The set-up is associated with obesity -- probably from lack of exercise and mindless snacking -- and even a higher risk of picking up smoking.

A 2005 study from researchers at Johns Hopkins and Stanford universities, for example, found third-graders with TVs in their rooms scored about 8 points lower on math and language arts tests, and 7 points lower on reading tests, than classmates without them. The best combination, the study showed, was no TV in the bedroom but access to a family home computer for schoolwork and educational games. A 2008 study from Israeli researchers, meanwhile, found middle schoolers with a TV in their rooms went to bed 30 minutes later (I'd guess that's actually a low estimate) and watched an hour more television each day.

Beyond any data, though, this just seems like common sense. If a kid has access to a TV away from a parents' eyes, who knows what he could stumble upon... accidentally or on purpose. Parents also would have no chance to explain confusing or disturbing scenarios on TV or use them as a launching pad to discuss family values. And I know a TV would keep my son awake; this is a night-owl kid who already kneels by his nightlight to read long after he's supposed to have been asleep. During one stretch, we had to take all the lightbulbs out of his room. Literally.   

We've never been the type of parents to ban TV or videos for our two kids, even when they were toddlers and my husband or I just needed them to sit and do something quietly for a little while. They don't watch a lot because they're very active, but sometimes we all just need a moment to chill out. To each parent his own, but I've never felt guilty that my guys can quote lines from SpongeBob Squarepants. Now, however, I think we need to draw a firm line.

My son dropped the issue fairly easily last night, luckily, but I'm sure it will be back. What do other parents think? Would you let your child have a TV, and if so what would be the rules?