Su BioNews un articolo di Alan Thornhill demistifica alcune paure diffuse riguardo la diagnosi genetica di preimpianto («Designer babies or designer news?», 15 maggio 2006):
PGD [Preimplantation Genetic Diagnosis] offers the choice for individual patients at risk of transmitting genetic disease to help prevent suffering for their families. PGD has never been about discrimination against people with genetic disease, cancer or disabilities. Neither should PGD be viewed as obstructing or removing the need for research into developing cures for genetic disease. Indeed, the production of embryonic stem cells from embryos carrying disease mutations, diagnosed using PGD, may actually accelerate progress towards a cure.
What about ‘designer babies’? The phrase is just too tempting to resist and unfortunately has entered the media lexicon. In reality, our choice of reproductive partner is the closest most of us will ever get to designing babies. Moreover, a simple thought experiment may help to alleviate fears that PGD will soon be used to design babies with selected positive traits such as intelligence. Suppose that only five genes code for intelligence – in fact, there may be hundreds – with each gene having a high and low performing allele (version). To get the desired combination of high intelligence alleles in just one baby, more than 5000 embryos would need to be tested. It would take a woman 40 years of continuous IVF with PGD to achieve this. In short, ‘designing’ babies using PGD is a non-starter.