By the example of deafness the article examines the ethical problems that arise when preimplantation genetic diagnosis is used for the intentional heredity of genetic defects. In the first two sections the relevant rules of the German Embryo Protection Law and the motives of deaf couples to desire a handicapped child are explained. Subsequently, it is asked whether the positive selection of genetic defects can harm or otherwise wrong the future child. Moreover, a possible duty of prospective parents to prefer an embryo which will most probably experience a higher quality of life is discussed. Finally, the question is raised whether parents have a right to refuse medical treatment that may alleviate their child's handicap. As a result, it is argued that neither a legal ban on the positive selection of handicapped embryos nor compulsory treatment of deaf children are ethically justified.