One of the primary goals of this contract is to determine the developmental toxicity of chemicals to which a wide segment of the population is exposed, especially women of childbearing age, Since it is difficult to asses exposure potential to developmental toxicants and outcome of exposure within this group, well-controlled animal studies provide a basis for human risk assessment. For this purpose, most studies will be designed to determine a dose-response relationship in addition to the detection of a potential for developmental toxicity. This contract is comprised of three tasks: developmental toxicity range- finding studies (Task 1), FDA Segment 2 developmental toxicity testing (Task 2), and evaluation of newborn pups from reproductive toxicity test systems contract (N01-ES-15323) for developmental toxicity (Task 3). The AIDS Option will test AIDS therapy drag combinations for developmental toxicity (Task 2). This contract will provide a resource to test NTP nominated chemicals and continue to improve testing systems in reproductive and development toxicology.