In vitro fertilization with pre-implantation genetic diagnosis allows couples who have an increased risk of passing a genetically inherited disease to their children to screen embryos before implantation. Screening embryos allows fertility specialists to remove embryos with chromosomal defects and use only health embryos for the embryo transfer procedure of IVF. PGD can also be used for gender selection, to prevent children being born with gender-linked diseases or to allow couples balance the gender of their family.
Pre-implantation genetic diagnosis works by identifying embryos that have defective chromosomes. Chromosomal abnormalities in embryos suggest children born from these embryos would have a genetic disorder. If PGD is used to help couples choose the sex of their child, fertility specialists identify embryos with an unbalanced number of male (Y) or female (X) chromosomes. Embryos with a higher percentage of one of the sex-identifying chromosomes are more likely to produce a child of the corresponding sex. MicroSort is a commonly used treatment method for gender selection that is combined with PGD. The procedure for in vitro fertilization with pre-implantation genetic diagnosis is the same as for traditional IVF until the embryo implantation stage. After the eggs and sperm have been collected and used to fertilize the embryo, the embryos are screened by fertility specialists and suitable embryos are selected for use in embryo transfer.
Gender selection is legal in many countries but remains a controversial addition to infertility treatments. Some countries, such as the UK, Australia and Canada, only allow sex selection if offspring is in danger of a sex-linked genetic disorder. In other countries, such as India and China, determining the sex of a fetus prior to birth is illegal, gender selection of any sort is also illegal. Yet, despite the limited availability and expense of sex selection procedures, its attractiveness is emergent. In countries where gender selection is legal, cost is still an issue. In the United States, IVF with PGD can cost up to $19,000, which is why many Americans find themselves seeking fertility treatment in places like Mexico, Costa Rica and other nearby countries. Some European countries, such as Germany and Italy have banned embryo freezing, egg donation and even embryo screening for genetic diseases, compelling couples to travel to countries where these treatments are legal. Some religions prohibit gender selection and for this reason PGD is banned in many countries.