PGD (preimplantation genetic diagnosis) - targeted examination of embryos to eliminate hereditary disease in families where one or both partners are carriers of disposition for the specific disease. This may be a chromosomal defect or monogenic hereditary diseases (the most common include e.g. cystic fibrosis - CF, spinal muscular atrophy - SMA, hemophilia and muscular dystrophy).
In the case of sex-linked diseases (e.g. hemophilia) it is possible to make a selection of embryos of the sex which does not have the risk of disease. Otherwise, selection of embryos according to sex is legally not possible. In terms of the observed disease only healthy embryos are transferred into the uterus, thus minimizing the risk of having an ill child or having to terminate the pregnancy in its course when fetal impairment is detected.
PGD can be used in those cases where prenatal diagnosis is not used for ethical reasons (e.g. for diseases that are manifested in adulthood, such as congenital predisposition to cancer).