Studies by Dr. Tyrone Hayes, however, found that at 0.1 ppb, atrazine feminizes the gonads of male Xenopus laevis and Rana pipiens larvae.  Atrazine-treated tadpoles showed evidence of hermaphroditismÑpossessing both testes and ovaries.  Testicular oocytes were present, and polynuclear oocytes were present in endocrine disrupted animals.  Hayes found similar problems in field collected animals from atrazine-contaminated areas.  Thus far, attempts to reproduce Hayes results have been unsuccessful.  One of the reasons that I would like to utilize atrazine in my study.