Final answer:
PGD is employed to prevent hereditary diseases such as sickle cell disease and muscular dystrophy, but raises ethical issues when used for non-health-related traits like beauty or intelligence.
Step-by-step explanation:
Prenatal genetic diagnosis (PGD) is a sophisticated medical procedure entailing the screening of embryos for specific genetic conditions. This technique is employed in conjunction with in vitro fertilization to help prevent the inheritance of certain hereditary diseases. Two genetic conditions that may warrant the use of PGD include sickle cell disease and muscular dystrophy, both of which are caused by specific alleles that can be identified and screened for prior to embryo implantation. The ethical landscape surrounding PGD is complex, particularly in relation to non-health-related traits such as physical beauty or intelligence. Using PGD for health purposes is generally less controversial because it aims at preventing diseases that could significantly impact the child's quality of life. In contrast, engineering for beauty or intelligence involves subjective attributes and raises profound ethical concerns regarding designer babies and eugenics. This involves the moral consideration of whether it is justifiable to alter embryos for reasons beyond health, and whether doing so could contribute to social inequalities or new forms of discrimination.