Abstract
Preimplantation genetic diagnosis is a form of very early prenatal diagnosis. The technique combines assisted reproductive technology with molecular genetics and cytogenetics to allow the identification of abnormalities in embryos prior to implantation. Since its introduction in 1990 this approach has been applied to an increasing number of single gene disorders, chromosomal rearrangements, and more recent indications such as aneuploidy screening and HLA matching. Since its inception the technology has attracted much attention: geneticists have expressed concerns about the robustness and validity of diagnosis based on single cell analysis, perinatologists were anxious about the effect of embryo biopsy on normal fetal development; and philosophers and ethicists have argued the cases for and against embryo selection. This article attempts to highlight the difficult choices and ethical challenges confronting patients and clinicians in an effort to balance the recognition of parental autonomy with the obligation of clinics to consider the welfare of any child born as a result of this treatment.