Pre-implantation genetic diagnosis

Pre-implantation genetic diagnosis (PGD) is defined as the testing of pre-implantation stage (before being transferred to the uterus) embryos for genetic defects and sex selection.

It is done when one or both parents have a genetic abnormality or for gender selection.  It requires in vitro fertilization and embryo biopsy and then the transfer of the chromosomally normal embryos in the uterus.