Yesterday I flew to Orlando and back with a woman who told me her boyfriend was very tall (6' 8"). My immediate reaction: Does he have Marfan Syndrome? I kid you not. After a beat, I said, "Sorry, that was the most glass-half-empty response I could have possibly had. Everyone else in the world probably asks if he plays basketball.
One more example to throw into the nature vs. nurture debate. I don't know if if makes it better or worse that my instincts are potentially correct: her boyfriend is having medical tests done.