Prenatal diagnosis of genetic disorders in preimplantation embryos: invasive and non-invasive approaches.

The purpose of this article is to analyse the various non-invasive and invasive methods that offer the opportunity of prenatal diagnosis of selected inherited disorders at the preimplantation stages of human embryonic development and to discuss the advantages and ethical problems associated with such procedures. These investigations should also provide important information on the development of the human embryo and its hormonal and immunological relationship with the mother.