My former best friend one day out of the blue told me he thought that women are on average smarter than men but are not capable of rising to the very top level of human intellect. His "proof" of this was the fact that nearly all major scientific discoveries have been made by men. Needless to say, he thought of himself as being at the highest level of human intellect - despite having made no major scientific discoveries himself (or even minor ones for that matter). This was the beginning of the end of our friendship, and I'm only embarrassed that it wasn't instantly the end of our friendship.