Towards the end of the 20th century, we were successfully beginning to understand part of the genetic basis of some human diseases. Up to that time, progress had been relatively slow, largely depending upon establishing familial associations, and some-what laboriously measured variations in candidate genes. This was usually in the form of single nucleotide polymorphisms (SNPs), measured one at a time with labor-intensive methods such as restriction fragment length polymorphism [1]. However, since the initial publication of work on the human genome [2], major advances in genotyping capability and reductions in cost, coupled with large collaborative population groups are enabling exponential advances in our understanding of human genetic variation. Genome-wide association studies (GWAS) are greatly increasing our understanding of the genetic basis of human disease, especially complex disease. Perhaps more importantly, they are more generally enhancing our knowledge of far more subtle differences between individuals, including behavioral characteristics, health, ‘wellness’ and performance. An analysis of GWAS publications since their first appearance in 2003 (fig. 1) emphasizes why Pennisi [3] described such studies as the breakthrough of the year in enabling knowledge of what makes each of us unique.