In some cases infertility problem is caused by congenital genetic problems of the female partner or male partner or both. Additionally due to their genetic disorders some couples, although they are not infertile, may need genetic analysis on embryos to ensure that they have healthy babies. Again although somewhat controversial, when repeated in vitro treatments fail, PGD can present an alternative for couples.

In this method two types of test and biopsy timing is possible; firstly for the test and analysis that require biopsy, biopsy is done on embryos that are 3 or 5 days old. Additionally FISH and NGS, two analysis methods can be recommended for the disorder to be screened. All of these are done with the necessary preparations before the treatment (for some genetic disorders, the genetic laboratory may need to take blood samples from patients for preparations than can take 1-2 months) Some diseases can be passed down with the sex chromosome (like haemophilia) and therefore the sex of the embryo can be important for screening for similar diseases. However the most important thing for the patients to know that the sex of the embryo is determined by the sperm that fertilizes the egg during the IVF procedure however we still do not have a method to know in advance whether the genetic load of a sperm is a male or a female and select the sperm accordingly. Therefore after the procedure, all embryos can be of either of the sexes.