In the 1980's, at age 37, Virginia Cover became pregnant with her second son. Amniocentesis revealed a diagnosis of Klinefelter syndrome, an extra X chromosome in a male. Cover and her husband had access to excellent genetic counseling, where they learned that Klinefelter syndrome is often associated with learning disabilities, communication and social skill deficits, and infertility. But there was little medical research available at that time, and no support resources for families. She made it her goal to develop a comprehensive guide to sex chromosome aneuploidy written in lay language. This book distills three decades of her experience as a parent and as a professional social worker into an authoritative guide for families and individuals affected by extra X and Y chromosome conditions. Often referred to as hidden disabilities, X and Y chromosome variations are the most common of the chromosome aneuploid conditions that may affect humans. They affect 1 in 500 persons. The result of the extra chromosome(s) is highly variable from one individual to another. Affected persons may be symptom-free, but more often will have symptoms including low muscle tone, speech delay, lowered fertility, learning disabilities, and sometimes autism spectrum disorders. Yet the public and many health and education professionals remain unfamiliar with the syndromes and their range of functioning, leading to missed diagnoses and lack of appropriate treatment. Mx. Cover provides a lifespan approach to the three trisomy conditions, Klinefelter syndrome, Trisomy X and 47, XYY (Jacobs syndrome), as well as their less common tetrasomy and pentasomy variations. The book provides clear explanations of the genetics involved, as well as diagnosis, disclosure, development from infancy through, potential health and fertility issues, and educational and psycho-social considerations.