To examine a possible influence of estrogen receptor variants on the genetic susceptibility to germ cell cancer we have analyzed the allelic frequencies of three polymorphisms within the estrogen receptor gene in testicular cancer (n = 454) and control populations (n = 672). There were no differences in allelic frequencies in cancer patients compared to controls. Subgroup analyses did not indicate differences in allele frequencies for any of the polymorphisms in those individuals most likely to be predisposed to testicular cancer (patients with a history of maldescent of testicles and/or infertility, patients suffering from bilateral testicular cancer, and patients with familial testicular cancer). The data do not indicate that variation in the 5' end of the estrogen receptor gene confers susceptibility to testicular cancer.