This year, scientists in China attempted to modify the genomes of human embryos. They were attempting to correct an aberrant gene that causes a blood disorder, beta thalassemia. Although the scientists used embryos that had been discarded as a result of IVF treatment, and although these embryos could not develop to term, the experiment raised concerns.Some scientists are calling for a moratorium on this work, and the Medical Research Council and Wellcome Trust have called for an urgent debate on the ethics of genetically modifying human embryos.Some say this is just a natural progression, the next step in eradicating devastating diseases that can blight lives. After all, scientists already test embryos in IVF clinics for genetic diseases and implant only the healthiest ones. Is this really so different? Others say yes, this is different. Because we are now capable of altering the DNA itself, any changes would be passed automatically from generation to generation.Furthermore, it would be all too easy to slide into uncharted territory. It's one thing to make changes that eliminate diseases such as cystic fibrosis or reduce the risk that an individual will be diagnosed with breast cancer. It's quite another to alter an embryo to ensure a baby is born with perfect pitch, an athlete's physique or a high IQ.If this possibility becomes reality, what might be the psychological consequences of creating designer babies?The first point to note is that a natural ability isn't the only ingredient needed to develop a particular talent. An individual must be strongly motivated to practise the many hours required to turn a nascent talent into a well-developed skill.Good teachers are needed, as well as a bit of luck. If parents "create" potential and then do not see it fulfilled, they might be disappointed. And worse, it will place an inexcusable burden on a child if it feels obliged to develop a particular ability simply to please its parents.Another worry is the issue of unintended consequences. I doubt that any human trait is detached and "clean" - all our qualities must be interrelated. Therefore, improvement in one area might blight another. For instance, it's often said (although not proven) that creative people are more vulnerable to depression. Surely no parent would request an intervention, however attractive, that might make their child more vulnerable to depression?The most distressing consequence, however, is that this technique could inadvertently compromise a child's ability to live most fully in the world in which they grow up. A particular intelligence or specific body shape might be considered highly desirable right now, but what if it becomes a liability in the future?If genetic modifications can eradicate diseases, let's welcome them. But if they're used merely as a means of satisfying parental expectations, we must carefully weigh those expectations against possible consequences. ..