The curse of risk aversion

This idea came to me while I was in my Micro class: we were talking about risk aversion and utility function: basically most of us are risk averse because our utility function is concave, i.e., we have a diminishing marginal utiltiy. In plain English, the disutility of losing one hundred dollars is bigger than the utility of gaining one hundred dollars.

Now suppose we have two people Johnny and Joe, they both are risk averse, but Joe is more so than Johnny. To put in another way, Joe's utility function is more 'concave' than Johnny's, and Joe needs more wealth than Johnny to reach a same level of utility. But this is unlikely to happen: our competitive society generally rewards risk-taking, not risk aversion, so Johnny will most likely do better than Joe. Hence there is the curse of risk aversion: you need(or want?) it more, but you will have less of it.

The question I wan to ask then is if our risk preference is more innate or cultured. I am leaning toward the latter, for that matter I guess we will all be better off when we are more willing to take risks.