Scientists have now found a name for it: T-types (that's with a capital T). Thrill seekers, novelty seekers, risk takers, those living on the edge.

If you prefer routine and certainty, on the other hand, you're a t-type (that's a small t).

Teams of researchers from Israel and the U.S. working independently announced that they discovered a link to a gene on a specific chromosome to behavior in people who seek "thrills."

Referred to as "novelty seekers," these folks appear to have in common a longer version of a gene known as D4DR on chromosome 11. This gene helps regulate a chemical messenger in the brain that mediates pleasure and emotion.

Scientists aren't saying this gene alone compels people to skysurf, snowboard or climb icy waterfalls, as upbringing and opportunity still influence behavior greatly. They also say that someone with the thrill-seeking gene could turn out to be a "hero in Bosnia," an extreme skier, or an ax murderer, depending on the circumstances.