PGD has been used to biopsy and analyze embryos created through in viuo fertilization (IVF) to avoid transferring to the mother’s uterus an embryo affected by a mutation or chromosomal abnormality associated with serious illness.’PGD to avoid serious and early-onset illness in the childto-be is widely accepted. PGD prevents gestation of an affected embryo and reduces the chance that the parents will be faced with a difficult decision of whether to terminate the pregnancy. More controversial have been PGD to select the sex of the child-to-be for “family balancing”(rather than to avoid a sex-linked dis~ rder),~ PGD for mere susceptibility to disease and for late-onset disorders such as Alzheimer disease: and most controversially, PGD to cre-ate a donor child who is Human Leukocyte Antigen (HLAI-matched with a preexisting sibling in need of stem cell transplant.’We convened an advisory group to discuss this last most controversial use of PGD to create a donor. The authors then developed this analysis of the clinical, ethical, and legal issues involved and devised recommendations. We were aided by direct knowledge of the fust reported case of successful use of PGD for HLA matching followed by hematopoietic stem cell transplant. The index case of Molly Nash involved IVF at the Colorado Center for Reproductive Medicine in Denver (by William Schoolcraft, MD et al.), PGD at Reproductive Genetics Institute in Chicago (by Yuri Verlinsky, Ph. D. et al.), and transplant at the Uni-versity of Minnesota (by John E. Wagner, MD et a1. Ie6 While others have analyzed a number of the issues