Don't go running to your chess board or Sudoku game just yet, though. As Arden notes: "This does not mean that men who prefer Play-Doh to Plato always have poor sperm." The link they found, based on data collected in 1985 from 425 Vietnam War veterans who volunteered for extensive medical and mental examinations, was marginal, she says. Yet, it was statistically significant enough to support the "fitness factor" theory—the idea that robust genes underlying intelligence, such as those that manifest themselves as artistic and musical abilities, could have biological effects on health (this is, of course, assuming that the differences in intelligence among individuals is driven by genetics). The theory goes against a competing one that ties lifestyle factors with the relationship between intelligence and health.