Embryonic origins of health: long-term effects of IVF in human and livestock.

Assisted reproduction technologies have been introduced 1) to overcome reproductive failures in the human, 2) to increase the number of offspring from selected females and 3) to reduce generation intervals in livestock in farm animals. The successful introduction of these technologies in clinical practice and in livestock breeding programs is the result of enormous scientific efforts. In general, the offspring generated by IVF (human) and IVP (cattle) is normal, but as numbers increase the restraints and drawbacks of new reproductive technologies become visible with respect to the overall efficiency as well as to the occurrence of abnormalities and/or anomalies in the offspring. The objective of the present symposium on "Embryonic Origins of Health" is to present "the-state-of-the-art" and to discuss the restraints and possible long term effects of the application of assisted reproduction technology in both human and livestock. This introduction to the symposium focuses on the relation between early embryonic development and post-natal health. We hypothesize that IVF in the human and IVP in cattle influence the timing of cell-cell interactions during the early stages of embryogenesis which finally result in a incorrect timing of gene expression during the phylotypic stage and subsequent organogenesis. These deviations in embryonic timing might have consequence for the postnatal homeostasis and health.