Sex chromosome aneuploidy is defined as a numeric abnormality of an X or Y chromosome and includes 45,X (Turner syndrome); 47,XXY (Klinefelter's syndrome); 47,XXX; and 47,XYY karyotypes. Individuals with 47,XXX and 47,XXY are generally fertile, but there is a risk of having a cytogenetically abnormal child in them. Turner and Klinefelter's syndromes are frequently associated with infertility, but few cases have been reported that they were able to give birth to a normal child as well as some children were born with similar or some other chromosomal abnormalities. Triple X syndrome occurs in 0.1% of live-born female newborns. Most of these newborns have a normal phenotype and only a few cases with 47,XXX karyotype have congenital malformations. These female patients may be mostly fertile, but there appears to be an increased risk of a cytogenetically abnormal child; the extent of this risk cannot yet be determined. Therefore, prenatal diagnosis and genetic analysis are therefore recommended. We report a rare case of triple X woman with a history of a Down syndrome child, for which she was advised a prenatal diagnosis in her subsequent pregnancy, and a review of other pertinent articles to establish the role of a prenatal diagnosis in parents with a sex chromosomal abnormality.