Final answer:
Choosing the gender of a baby can prevent the inheritance of sex-linked disorders. PGD is used to analyze the embryo's sex chromosomes, enabling the choice of a gender less likely to be affected. Ethical considerations are notable as different countries have varying regulations governing the non-medical use of sex selection.
Step-by-step explanation:
Choosing the gender of a baby can help parents who fear passing on a sex-linked disorder by selecting an embryo of the gender less likely or not at risk to develop the disorder. Disorders like Hemophilia and Duchenne Muscular Dystrophy are primarily linked to the X-chromosome, and since males have only one X chromosome inherited from their mother, they are more likely to express these disorders if that X chromosome carries the mutation. Prenatal diagnostic techniques such as Preimplantation Genetic Diagnosis (PGD) allow the examination of an embryo's chromosomes before implantation, thus giving parents the chance to choose an embryo of a specific gender, for example, a female embryo if they want to minimize the risk of having a child with a disorder that is dominant on the X chromosome.
It's important to note that ethical considerations arise with the non-medical use of such technology. Countries have different regulations about using sex selection for reasons other than preventing genetic diseases. Some restrict it strictly for medical purposes, while others allow for more personal reasons such as 'family balancing'.