An idea just came to me. Am I short because I wrestled in high school, or did I wrestle because I'm short? I'm pretty sure it's the latter, but I was talking with some fellow former 103-pounders at my high school reunion last month and one said something to the effect that he thought he'd be a couple inches taller if he hadn't cut serious weight that one year. Also I just happened to think at the reunion "I felt a lot shorter than all these people in high school, but not so anymore" and I've just now realized that all the people I thought that about were wrestlers, but it could just be that I was wearing Skechers with thick soles. Anyway.) It's well known that stunting happens from malnutrition at really early ages, but I'm thinking about TB, who was the same height as me all through junior high, but then took off our last year of high school (after getting a job at Popeye's, with access to unlimited chicken). So how could I get exogenous variation in the amount of wrestling to get at the causality? Title IX, that's how.
I really doubt the height thing would work (where is there good height data on US high schoolers?), but there's got to be a more serious question that one could answer (college admissions? SAT scores?) using variation in sports offered at public schools. Any thoughts?