The tired old chestnut "It happens to every guy" may soon be replaced by the much more scientific "It's in your genes," according to a recent study that links premature ejaculation to DNA.

A study of nearly 200 Dutch men found those with a certain version of a gene that controls serotonin ejaculated twice as quickly as the others. To gather the study's data, the volunteers' female partners were asked to use a stopwatch at home to measure how long it took the men from the starting line to finish gate. (To be fair, having sex while your wife times you with a stopwatch seems like enough to make anyone a little sensitive.)

For the quick finishers, serotonin appeared to be less active between the nerves in the section of the brain that controls ejaculation. Paula Hall, a sexual psychotherapist for Relate, said the men with primary premature ejaculation tended to be fast reactors in general. "These men have very quick reflexes. They may be excellent at playing tennis or computer games, for example."

Well, at least men with this affliction can console themselves by really walloping their well-timed-ejaculating buddies at a rousing game of table tennis or Donkey Kong.