By now we’ve all read the recent ESPN story on all the crazy, hard-bodied sexual shenanigans of the Olympic Village. They bought 100,000 condoms to satisfy the late-night humps and rumps at the Olympic Village. Then, yesterday, Olympic swimmer Ryan Lochte’s mother aired out all his business, inexplicably discussing her son’s sexual habits on the set of NBC’s Today show, explaining, “He goes out on one-night stands. He’s not able to give fully to a relationship because he’s always on the go.”That’s, um, extremely awkward. But what’s the science behind one-night stands? Why do some people take the merry-go-round route of sexual exploits--plenty of them aren’t Olympians with a unyielding training schedule--while others don't part till death? A couple of years ago a research team led by Justin Garcia, a SUNY Doctoral Diversity Fellow in the laboratory of evolutionary anthropology and health at Binghamton University, found that your severe case of dick or vagina ADD isn't your fault. According to his research, a propensity for casual sex appears to be genetic. One of the biggest predictors for an individual’s risky sexual behaviors seemed to be a certain variant of the dopamine receptor D4 polymorphism, or DRD4 gene. This gene is also closely linked to other compulsive, risk-taking behaviors like gambling and alcohol use. Now, these genes don’t “make” anyone do anything. A single gene’s expression exists within a system of many other genes, and all of our behaviors are also dependent upon our cultural and value systems, things that are at least partially due to external factors. But, the variant of DRD4 found to be closely related to histories of uncommitted sex changes the way that dopamine—a powerful reward chemical—is released when a person indulges in risky behaviors. So while it might not force anyone to engage in a one-night stand, it probably takes the shame out of it.Now, 50 years ago, no mother would ever have spoken with a national news outlet regarding her son’s one-night stands. Lochte would probably have had a nice girlfriend cheering him on from the stands. So it’s certainly not simply a matter of genetics. Plenty of people possess the variant of the DRD4 gene in the 50s, and while people will always have casual sex, it was not nearly as prevalent and socially acceptable then as it is today.Read the rest at Motherboard.