Developmental toxicology: methods and protocols. Volume overview: introduction.

The origins and history of the study of teratology and developmental toxicology span centuries of human experience. Anatomical malformations observed at birth have been described across many generations but the root causes of these events have been enigmatic and difficult to understand. Many factors may contribute to the lack of mechanistic understanding, but the miniscule size, inaccessibility, and the consequences of ethical concerns contribute heavily to the unique restrictions on developmental toxicology research. Classic teratogens, such as vitamin A, Rubella virus, thalidomide, and methyl mercury, have provided many insights into understanding the modes of chemical action that are responsible for causing defects but the specific mechanisms remain unclear. Developmental toxicology research has benefitted greatly in the past decades from discoveries made in related fields of study, including those from cancer research, stem cell biology, and developmental biology. New methods created and adapted for studies in developmental toxicology have taken on greater importance as gestational lesions can now be shown to have developmental and health consequences across the entire lifespan.