This study was conduced to assess the effects of a one time embryonic exposure to p,p'-DDE (dichlorodiphenyldichloroethylene; DDE) on the reproductive development and function in Japanese quail (Coturnix japonica). Embryos were exposed at day one of incubation to either 20 or 40 microg DDE or a sesame oil vehicle control (injection volume=20 microl). Onset of puberty, gonadal histopathology, sperm motility, cloacal gland size, and male copulatory behavior were assessed in adults. DDE accelerated onset of puberty in females and reduced male reproductive behaviors. Gonadal morphology and sperm motility appeared to be unaffected. Results from this study provide evidence that the neuroendocrine system may be more sensitive and less resilient to embryonic exposure to contaminants than traditional measures of reproductive success following contaminant exposure in adults. This study further supports the inclusion of behavioral assessments in toxicity tests.