I must admit, that when I first heard of this, I was as ignorant as some of you must be. The tale goes that some people, pregnant women in particular, can leave stains on the seat of the toilet when they visit the bathroom. What makes this such an intriguing mystery is that some people have reported the staining to be blue. It turns out, the stain is due to a chemical reaction between certain toilet seats and certain fats in our sweat. Newer toilet seats have an...