Logical Fallacy

Dicto simpliciter: A sweeping generalization and expecting it to be true in every case. An example would be that most men are faster than women. This on average is probably true but is not true because there are women out there that are faster than men, like I bet Marion Jones is faster than me, but I didn't take steroids. I have made generalizations lots of times without thinking them through, for example when I was young I told my mom I was stronger than her, and she asked why? I responded, because I am a man. She proceeded to pick up a chair and asked me if I could, I tried and was not able to, therefore proving my mother's point.

http://www.csun.edu/~dgw61315/fallacies.html#Introduction