Culture and quality control of embryos.

Improvement of embryo quality during in-vitro culture can be achieved by understanding and controlling the requirements of gametes and embryos. The most obvious route is to alter culture media, but standardization could be influenced by diverse environmental factors. Abnormal embryos from patients with multiple failures probably do not benefit from standardization and require specialized therapy, that is if their physiology is not already irreversibly jeopardized during gametogenesis. This paper describes the adverse environmental factors present in laboratory air and released by common products used by laboratories. Assays and results of the air determinations in several laboratories are reported, as well as potential counter measures. The possibility of altering the immediate environment of the nucleus of the egg by ooplasmic transplantation is also considered, and the first attempts resulting in two ongoing pregnancies are reported.