[Rain Man]

I always envision these studies as big massive questionnaires that the researchers then do regressions on to try to find some relationships. So they find a bunch of bad dads and a bunch of good dads, and they ask them all sorts of questions like,

"How large are your testicles?"
"Do you eat pizza slices from the crust in, or the point out?"
"How many horsepower does your car have?"
"Did you cry at the end of Titanic?"
"Would you rather score with a Czech woman or a Romanian woman?"
"Would you rather know how to play the saxophone or the violin?"
"How many credit cards do you carry?"

And then some grad students cranks the numbers and excitedly tells the professor, "Hey, I found a correlation with testicle size!"