The process of PGD involves several steps. First, eggs are retrieved from the ovaries and fertilized with sperm in a laboratory setting. Once fertilization occurs, the embryos develop for a few days until they reach the blastocyst stage. At this point, a few cells are carefully removed from each embryo. The genetic material in these cells is then analyzed for specific genetic mutations or chromosomal abnormalities. Only embryos that are free from the targeted genetic issues are selected for implantation.