Preimplantation Genetic Diagnosis, we shorten that as PGD, is a technique where we can take a biopsy of the embryo on day three of life, or on day five of life, we can take multiple cells. We can send those cells off to a lab to be evaluated for a specific genetic defect that either the patient or her partner may be a carrier of. We do this in an effort to transfer embryos that might not be affected by that genetic defect. There is also something called Preimplantation Genetic Screening. We shorten that with PGS. Essentially, what that is, that we also take a biopsy of an embryo on day three or day five of life, but we send those cells to be analyzed just for the chromosomal number. This is not routinely done yet. There are still some kinks that are being worked out. The goal of this procedure is that we transfer an embryo that is chromosomally normal.