Endometriosis is a complex gynecologic disorder that has long been recognized as showing heritable tendencies, with recurrence risks of 5-7% for first-degree relatives. Familial and epidemiologic studies support that this disease is a genetic disorder of polygenic/multifactorial inheritance. The current investigational challenge is to determine the number and location of causative genes. Recent advances in molecular technology make identification and elucidation of these genes now possible. In this review, we update previous communications in which we also reviewed heritability studies supporting polygenic/multifactorial inheritance, discuss the scientific basis of genomewide strategies for identifying causative genes, and identify potential candidate genes.