I picked up the second season of Penn & Teller: Bullshit! on DVD on Saturday. It's a TV series on Showtime that attempts to debunk things they believe to be unscientific (albeit somewhat one-sidedly). It's an interesting series to watch, and while some things they debunk should be obvious to most people, others are not (and they may not always be right). The point is to remind their viewers to be more analytical and better informed when someone tells you something passed off as fact, especially if it's something that would cause you to change your lifestyle or perceptions.
For instance, my mom recently forwarded me an email warning about saccharin--that it's been found to cause cancer in lab rats. The email further confuses the issue, as it seems to think all artificial sweeteners are the same--it's mostly in Chinese, and seemed to be talking about aspartame (阿斯巴甜) through most of the email, but uses "saccharin" in English near the end of the message. These are two very different artificial sweeteners. (Yet another different artificial sweetener is sucralose, known to most of us as Splenda, although this was not mentioned in the email.)
I dislike all of the artificial sweeteners I've tried, so it makes no difference to me anyway, but this was something that I've known about for years--back when the warning label was on the Sweet'n Low packages (which is what most of us know saccharin as, or "the pink stuff"; aspartame, on the other hand, is typically known as NutraSweet, and also the main ingredient in Equal).
If you go out and find some Sweet'n Low packages today, you'll find that they no longer carry the warning about saccharin. That's because they've found out that the original lab tests that say saccharin caused cancer was tempered with--the "scientists" purposely gave the lab rats an insane amount of saccharin, which gave them cancer. If you gave those lab rats the same amount of anything, it would be just as bad. So, the warning was removed.
How do I know this? Well, a few years ago, as I was about to warn some friends about Sweet'n Low by showing them the warning label, I couldn't locate the warning on the packaging. Afterwards, I searched to find out why they would be able to remove such a serious warning from their packaging.
But don't take my word for it.