Yin/Yang blue purple by Jacques Deshaies (2002) (detail).

More than 1,000 children have been born following preimplantation genetic diagnosis (PGD). PGD use is likely to grow over the next decade, mostly as a tool for detecting aneuploidies in in vitro fertilized (IVF) embryos but also for screening an increasing number of mutations that are related to health and disease1. Some have decried these steps as moves towards creating “designer children”, but I believe recent evidence fails to support this view.

First developed as an alternative to amniocentesis for screening embryos for autosomal and sex-linked diseases, PGD is now used to screen for other genetic mutations, for disease susceptibility and to identify prospective children who can make haematopoietic stem cell donations to existing children1. Unless one objects to screening embryos (and many do), these practices should be ethically acceptable to those who otherwise accept PGD.

More controversial is PGD for non-medical uses, such as sex selection, because it is feared that sex selection, particularly of firstborns, entrenches pro-male, sexist social attitudes. The ethical assessment shifts, however, when the sexes of only second, or later, children are chosen. If no sex is disproportionately favoured, the threat to women and the risk of unbalanced sex ratios are considerably reduced. Ethical debate then focuses on whether desire for family 'gender balance' justifies IVF and embryo screening2. While many will oppose this practice, we are likely to see an increased acceptance of PGD for this use.

Until genes for other phenotypic traits are identified, embryo screening for other non-medical purposes is less likely to occur. Potential candidates at present include the GJB2 gene mutations, which are the largest known contributor to inherited deafness3. Individuals with a family history of deafness might request PGD to screen for GJB2 mutations, therefore raising concerns about prejudice to the deaf community. If screening could occur without hurting the rights or interests of deaf people, its use to ensure a hearing child might be accepted. However, what if deaf couples want to screen for embryos with these mutations? In addition to questions about whether embryos should be discarded for such a choice, the ethical issue is whether being deaf, instead of hearing, will hurt a child. Given the rich culture now available to deaf people, many bioethicists would accept the deaf parents' choice4.

These examples illustrate the ethical issues that might arise from new uses of PGD. More debate is clearly needed, but evidence indicates that, when new uses of PGD help parents to have healthy, wanted children, society is likely to accept them. If so, public authorities should focus on ensuring the techniques' safety, reliability and availability, and not on stopping PGD as the harbinger of “designer” children.