In the 2002 American Society of Reproductive Medicine annual meeting held in Seattle, a rather confident prediction was made that within about five years, at least one endometriosis susceptibility gene will be identified. Seven years have since passed mercilessly, yet so far not a single gene has ever been or is close to be identified. This failed prediction seems to echo Niels Bohr’s famous quote: “Prediction is very difficult, especially about the future.” Difficulty in predicting future aside, for an enigmatic disease such as endometriosis for which etiology is poorly understood and, consequently, there is a pressing need for novel efficacious therapeutics with low side-effects profile, an interesting issue is why the prediction failed to materialize in the first place, or whether this prediction will ever, albeit belatedly, be materialized at all. Indeed, there is a burgeoning interest in the identification of genes or DNA variants that predispose women to endometriosis. A PubMed search with the words “endometriosis” and “polymorphism” showed that, starting from 1996, in which the first report on genetic association of endometriosis with GSTM1 polymorphism was published, the number of publication has since grown roughly exponentially.