PGD is abbreviation of Pre-implanation Genetic Diaanosis. It is a procedure for testing the genetic makeup of very early embryos created through in vitro fertilization (IVF) and involves removing a cell from the developing embryo conceived IVF to identify whether it has X or Y chromosomes.

At early stage, an embryo has about eight identical cells, which have started to multiply but not yet begun to differentiate. When one cell is extracted, the remaining cells can develop into a complete fetus.

Pre-implanation Genetic Diaanosis (PGD) can be used to select embryos that do not have a particular genetic sequence. It can also be used to determine the embryo's sex, i.e. Sex selection.