Tyrone Hayes, a biologist at the University of California, Berkeley, has spent over a decade researching the effects of the herbicide atrazine on frogs. His research found that atrazine causes demasculinization and hermaphroditism in male frogs and may be a factor in the worldwide amphibian decline. However, the manufacturer of atrazine, Syngenta, disputes Hayes' findings and has attempted to undermine his research and reputation.