2 March 2009
In scientific terms, a certain degree of selection for genetic traits that exert a major influence over hair, eye or skin pigmentation is feasible [Sulem P et al. (2007) Nat. Genet. 39:1443-1452], although the presence or absence of a specific genetic variant in an IVF embryo would not guarantee that a child developing from that embryo would have the desired physical features. The clinic does not appear to be claiming reliable prediction of cosmetic traits. Of note, the number of embryos produced by IVF is typically very low, so that there would only be a small number to select between for implantation and hence limited availability of embryos that were genetically different with respect to the characteristics of interest.
Further, implantation of an embryo by no means guarantees that a pregnancy will result; f.or example, recent UK figures suggest that the probability of pregnancy following one cycle of IVF treatment is up to 31% for women under 35, dropping sharply with increasing maternal age. The capacity to select embryos in order to produce babies with specific physical features is therefore very limited. However, many are of the opinion that any attempt to select for features that are not related to the health of children born following IVF is unethical.
Hitherto, preimplantation genetic diagnosis (PGD) has been limited to determination of the presence or absence of a genetic variant associated with a serious form of disease; in the UK, this is the only permitted use of the technique, which is carefully regulated by the Human Fertilisation and Embryology Authority (HFEA). Only UK couples with a family history of serious inherited diseases (or significant inherited predisposition to serious diseases, such as familial breast-ovarian cancer syndrome) are offered PGD; the probability of serious disease in the embryos of other couples is very low. Sex selection via PGD is only permissible in the UK where there is a chance that the embryos may be affected by a serious sex-linked genetic disorder that affects only males or females.
In the US, services providing PGD are subject to voluntary regulation. The American Society of Reproductive Medicine has issued guidance on pre-implantation genetic diagnosis and screening, which sets out the indications for using these techniques. Although the majority of clinics providing assisted reproduction are members of the American Society of Reproductive Medicine, it is possible that in some circumstances clinical judgments could be influenced by the fact that the majority of IVF within the USA is funded privately. Those paying for treatment might be anxious to exercise as much choice as possible over resulting offspring. It also seems possible that couples paying for IVF treatment could be 'misled' about the probabilities of embryos being affected by serious diseases, in order to persuade them to opt for additional screening. On the other hand, private funding by individuals may also may make it difficult for clinicians to exercise unfettered clinical judgment, as the recent controversial Suleman case seems to suggest. The limited capacity to select embryos for cosmetic traits could be considered a logical extension of parental choice in a regulatory environment that permits sex selection for social (ie. non-medical) purposes.