text: Pre-implantation genetic diagnosis (PGD) is criticised for giving select demographic groups disproportionate access to a means of creating a child possessing characteristics that they consider "ideal". Many fertile couples now demand equal access to embryonic screening so that their child can be just as healthy as one created through IVF.  Mass use of PGD, especially as a means of population control or in the presence of legal measures related to population or demographic control, can lead to intentional or unintentional demographic effects such as the skewed live-birth sex ratios seen in China following implementation of its one-child policy.
  While PGD was originally designed to screen for embryos carrying hereditary genetic diseases, the method has been applied to select features that are unrelated to diseases, thus raising ethical questions. Examples of such cases include the selection of embryos based on histocompatibility (HLA) for the donation of tissues to a sick family member, the diagnosis of genetic susceptibility to disease, and sex selection.
  These examples raise ethical issues because of the morality of eugenics. It becomes frowned upon because of the advantage of being able to eliminate unwanted traits and selecting desired traits. By using PGD, individuals are given the opportunity to create a human life unethically and rely on science and not by natural selection.
  For example, a deaf British couple, Tom and Paula Lichy, have petitioned to create a deaf baby using IVF. Some medical ethicists have been very critical of this approach. Jacob M. Appel wrote that "intentionally culling out blind or deaf embryos might prevent considerable future suffering, while a policy that allowed deaf or blind parents to select for such traits intentionally would be far more troublesome."