Designer babies, conceptual illustration. Row of foetuses overlaid with a DNA autoradiograph 'genetic fingerprint' (rows of blue and black bands). This could depict gene manipulation in gene therapy, cloning, or adapting the baby's genes to give specific characteristics to order. Gene therapy is the treatment of medical conditions caused by malfunctioning genes. This often involves administering a corrected version of the defective gene to the patient so that they can use it to function normally.