From Wikipedia
I thought that I should post this.
And, would this affect LDing?
The only light that I have is my clock (dim) and my radio. The most annoying light is my radio light though. I have never heard that having a light on could cause cancer. Having a light on would not effect on LDing. If you have trouble going to sleep with the light on then I would turn it off.
I keep my lamp on at night because I have an enormous fear of and a bad reaction to total darkness. It feels like someone’s smothering with me when I’m in it.
That said, I don’t think it does. I have an LD once a week and I’ve slept with my lamp on for years.
Also, I never really pay attention to things like that unless there have been multiple studies and all. It even states “tentatively suggested”. You could probably link almost anything to cancer or anything else with even the barest thread, after all.
I sleep with my TV on and my fish tank light. But, I think I might turn off my fish light tonight.
Last night I did, and I had really good dream recall.
But, I’m not sure if it had anything to do with it.
But, I’m going to experiment. 
I sleep with my alarm clock light, its pretty bright and sometimes keeps me awake. But i dont think, and hope that it as no effect on you (like cancer and such)
(Time to let my inner nerd shine!!!)
I’ve never heard anyone relate melatonin to cancer before. However, sleep is when the body rejuvenates itself, and lack of sleep does attack the immune system. In theory, if the immune system is serriously, serriously hampered by lack of sleep, there might be a greater risk of getting cancer. But in my opinion, I don’t see that happening to 99% of the population. Also, if a person can get healthy sleep even with a light on, as in Remedium’s situation, I don’t see the problem.
This definitely sounds like another cancer scare. 
You can get cancer from just breathing the air, since it contains traces of radiation natural on our planet.
I think you have more chance of being hit by a bus first thing on a morning than getting cancer from any single “possibly linked” cause.
As far as sleeping goes, I need to be in almost total darkness to sleep best. The less light the better.
Studies done on mice shows that melatonin has significant protective qualities against cancer, the mice were exposed somewhat cruelly to a severe carcinogen, those with the melatonin supplement fared a good deal better than those without.
So there probably is something in it. Also, since melatonin is a well known dream aid, increasing vividness and recall, it would make sense that a lack of it would cause the opposite, ie: less recall and less vivid dreams.
no i dont . Already because if i would my dad or mom would turn it off
I never sleep with the light turned on 
I simply cannot fall asleep then -_-
For some reason the TV makes me sleepy… But my LCD computermonitor does not have the same effect. Could the light from the tv have a certain something to do with this?
I don’t sleep with lights on, but I do sleep with shutters and curtains open.
Note that my room’s windows is directed toward North, so in summer, my sleep isn’t interrupted by sunlight.
Regardless, I noticed that my dreams are more lighted up.
So, north light doesn’t disturb my sleep/dreams, quite the contrary, it gets them better.
I think there’s been a lapse of logic somewhere. Does the melatonin directly prevent cancer or does sleep in general?
All I know for a fact about melatonin is that it is a hormone that makes you sleepy–> sleep–> better immune system–> less cancer?
If direct evidnece side-steps the whole “more sleep means you’re healthier,” please let me know. 
It’s melatonin. Whilst getting the right amount of sleep allows your body to repair itself, it is melatonin that has been shown in studies to directly inhibit the growth of cancers.
All right, thanks.
Huh. That would explain why we have more cancer cases these days, with all this artificial lighting after dark.
I sleep with the lights off. The only lights in my room are little lights from my PS2, computer, and the DVD player on my computer which has a blue light, but it’s not very bright. I tend to bury my head under a pillow or the covers anyway. When I was little I used to sleep with a small lamp, though. It was bright enough so you could see the whole room, but it wasn’t blinding.
I sleep in a very dark room, b/c my eyes are sensitive to light. But I have always had good recall, even a few years ago when I had to have a nightlight b/c my sister and me shared a room…no idea
When your tired enough though, doesn’t your body kind of “make you sleep”.?
Well, technically most everything causes cancer. I mean come on. Sunlight, normal light, red meat, sitting down, EVERYTHING!!! It does by the teeniest ammount. Scratching your arm might cause irritation, eating cheese might make you constipated. Lights might make you have cancer, though its very unlikely, it MIGHT. Deal with it.
It is not just “lights”…it is “lights on while you are sleeping.”
And you can prevent skin cancer by wearing sunscreen when you are outside for a long time. I mean, it’s kinda hard to get cancer…unless it is something that you cannot prevent. If it is skin cancer, it probably could of been your fault because you didn’t wear enough sunscreen.
Anyway, having the lights off when you are sleeping may help prevent cancer…and if you do, it probably won’t make a huge difference.
And…ummm…what does cheese and constipation do with cancer???
Or scratching your arm??? 
lol I meant by the scratching/cheese thing that EVERYTHING might do something bad. And what I was getting at was it doesnt make a big difference. Everyday we do things that cause cancer. Most people dont get it. It probably won’t make or break your chances of getting cancer.