Even in rats, which are much more sensitive than humans to perchlorate, it takes extremely high doses of perchlorate (above 14,000 ppb) beyond what would ever be found in nature or drinking water to generate an adverse health effect.
York et al. This study looked at whether perchlorate causes birth defects in rats. No adverse effects were found in either rat mothers or fetuses at doses of perchlorate equivalent to 1,050,000 ppb in water. The study confirms perchlorate is not a reproductive toxicant. View Abstract
Bekkedal study. This study tested the motor activity of baby rats whose mothers were exposed to varying doses of perchlorate equal to 3,500 to 350,000 ppb. The study found no significant differences between rat pups whose mothers were treated with perchlorate and those whose mothers weren't. It confirms the findings of an earlier neurobehavioral development study of perchlorate's effects in rats.