97IntroductionThe use of preimplantation genetic diagnosis (PGD) is rapidlygrowing and in coming years is likely to continue to grow. PGDis now used primarily for aneuploidy screening, to identifychromosomal translocations, and to avoid the transfer ofembryos with autosomal and X-linked Mendelian early onsetdiseases (International Working Group on PreimplantationGenetics, 2001). In addition, some persons seek PGD in orderto have an HLA-matched child to provide haematopoietic stemcells for an existing child and for non-medical gender selection.Some commentators predict that PGD will eventually be usedto screen for other non-medical traits as well.This paper discusses technical and ethical factors that will affectfuture applications of the technique, and provides a methodologyfor resolving ethical conflicts about new indications for PGD. Itthen illustrates that methodology by examining one medical andtwo non-medical extensions of PGD.Technical and economic factorsThe scope of future application of PGD depends on manyfactors both technical and ethical. Unless the technique workssafely and effectively at a reasonable cost, it will play but asmall role in the reproductive plans of most individuals. TheIVF on which it depends must be safe, effective, and within thefinancial means of persons who would benefit from it. Inaddition, the personnel and resources for highly accurate PGDmust also be available. While many IVF clinics are equippedto remove the individual cells needed for chromosomal orgenetic analysis, fewer of them will have the expertise to dochromosomal and genetic analysis to the highest levels ofaccuracy necessary for wide dissemination of PGD. A systemof reference centres organized on a regional or even nationalbasis may have to be developed to provide the quick andaccurate analysis needed.A second important technical factor is the state of genetic andgenomic knowledge. The most prevalent single-gene disordershave now been identified, and PGD is available for most ofthem. With most of the low-hanging genetic fruit now havingbeen picked, scientists will have a harder time identifyingother single gene mutations for diseases and non-medical traitsthat are of potential interest to future parents, particularly sincedevelopmental and environmental factors may play a moreimportant role than single genes or clusters of genes in causingthe chronic diseases of widest concern. Similarly, few of thenon-medical traits of apparent interest to prospective parents,e.g. intelligence, height, beauty, memory, longevity, etc, areEthics and the future of preimplantation geneticdiagnosisJohn A Robertson holds the Vinson and Elkins Chair at The University of Texas School ofLaw at Austin, USA. He is the author of Children of Choice: Freedom and the NewReproductive Technologies (1994), and numerous articles on reproductive rights, genetics,organ transplantation, human experimentation, and other issues in bioethics. He servescurrently as Chair of the Ethics Committee of the American Society for ReproductiveMedicine.University of Texas Law School, 727 East Dean Keeton Street, Austin, TX 78705, USACorrespondence: e-mail: [email protected] A RobertsonAbstractThe future growth of preimplantation genetic diagnosis (PGD) will depend on refinements in genetic knowledge and geneticanalysis of blastomeres. Equally important, however, is an acceptance of the ethical legitimacy of parents using technologiesto select genetic traits of offspring. Objections based on embryo status, the giftedness of reproduction, eugenics, andprotecting the child’s welfare are not convincing grounds to oppose most uses of PGD. Whether PGD should be acceptedfor new medical or non-medical uses should depend upon a careful assessment of the proposed use’s importance to theperson or couple requesting it, and the harmful effects, if any, which it might cause. Such an approach leads to the conclusionthat most new medical uses of PGD and some non-medical uses should be permitted.Keywords: embryos, deafness, eugenics, preimplantation genetic diagnosis, regulation, sex selectionRBMOnline - Vol 10. Supp 1. 2005 97–101 Reproductive BioMedicine Online; www.rbmonline.com/Article/1626 on web 31 January 2005Ethics, Law and Moral Philosophy of Reproductive Biomedicine, Vol. 1, No. 1, March 2005© 2005 Reproductive Healthcare LimitedPublished by Reproductive Healthcare Limited98Ethics - Ethics and the future of PGD - JA Robertsonlikely to correlate with mutations in a few genes or loci thatcan be easily tested by PGD.The use of microarrays, which allow transcripts of thousandsof genes to be tested at one time, could expand the reach ofPGD. However, unless genes predisposing to conditions ortraits of interest to prospective parents are expressed at theblastomere stage, microarray tests will be of little use. Even ifthey can identify single nucleotide polymorphisms (SNPs)associated with those traits, SNP tests of blastomeres might notprovide specific enough information for selecting among therelatively few embryos available for testing that are also likelyto implant in the uterus. On the other hand, a rapid growth ingenomic knowledge and advances in microarray technologycould lead to much wider use of PGD for both fertile andinfertile couples.A third factor limiting future use of PGD is its cost. IVF itselfis expensive, and adding on PGD will increase that cost.Persons considering reproduction will incur those costs onlywhen the burdens of infertility, the risks of genetic disease, orthe desire for a particular trait in a child are great enough tojustify the financial and physical burdens of the process. Whilean argument can be made for national health insurancecoverage of basic IVF for infertility (as the UK’s NHS hasrecently done), the case for covering IVF and PGD is a moredifficult one (Ashcroft, 2003). It is strongest when a stronghealth need for PGD exists, for example, to have a matchedsibling donor for an existing sick child or to avoid a child witha severe genetic disease, and weakest when sought for non-medical and susceptibility purposes. Because many otherprojected uses of PGD will not warrant insurance coverage, e.g.PGD for gender