Designing babies: what the future holds.

Advances in reproductive technology have opened new opportunities to avoid inherited diseases in offspring. The preimplantation genetic diagnosis (PGD) of human embryos permits those embryos carrying gene disorders or a non-diploid chromosome constitution to be identified. Numerous disease genes including those with a late onset have been identified and the conditions averted in children. Risks of abortion have been reduced, and the incidence of live births raised after PGD. It is also possible to select embryos with human leukocyte antigens (HLA) identical to those of a sick elder sibling, and then use stem cells from cord blood at birth to supply the necessary therapy. This form of treatment has alleviated the inherited disease in many recipients. The outlook and ethics of this approach to the alleviation of human disorders are discussed.