The chances of a woman having a chromosomal abnormality on a Down’s test after three generations of IVF are not high. Abnormalities in the number of chromosomes in form or structure are known as chromosomal abnormalities. Diseases caused by chromosomal abnormalities are called chromosomal disorders. The third generation IVF technique is used to analyze the genetic material of the embryos during embryo selection to exclude embryos that carry known disease-causing genes. However, it is not possible to fully guarantee 100 percent accuracy of the diagnosis during this process. So it is also possible to have chromosomal abnormalities. But because the chromosomal screening has already been performed once, the chances of chromosomal abnormalities are reduced when Down’s screening is performed, so there are very few women with Down’s screening chromosomal abnormalities in three-generation IVF.