Caption:
Composite Scanning Electron Micrograph (SEM) of human chromosomes, showing two X and one Y chromosome, as is found in Klinefelter syndrome. This is a genetic disorder in which there is at least one extra X chromosome to a standard human male karyotype. Common effects include reduced fertility, enlargement of the breasts, smaller testes, and reduced facial and body hair. Some individuals also have learning disabilities and/or behavioural problems.