Unless the environmental load of synthetic hormone disruptors is abated and controlled, large scale dysfunction at the population level is possible. As attention is focused on this problem, more parallels in wildlife, laboratory, and human research will be revealed. For example, many sex-related characteristics are determined hormonally during a window of time in the early stages of development and can be influenced by small changes in hormone balance. Evidence suggests that sex-related characteristics, once imprinted, may be irreversible. Reproductive effects reported in wildlife should be of concern to humans dependent upon the same resources, e.g., contaminated fish.
Food fish is a major pathway of exposure for birds.
Information is limited concerning the disposition of these contaminants within humans, especially data on concentrations of contaminants in embryos. While there are adequate quantitative data concerning reduction in reproductive success in wildlife, data are less robust concerning changes in behavior. The evidence, however, is sufficient to call for immediate efforts to fill these knowledge gaps. The potencies of many synthetic estrogenic compounds relative to natural estrogens have not been established. This is important because contemporary blood concentrations of some of the compounds of concern exceed those of internally produced estrogens.