Until relatively recently no practical method was available for the determination of the genetic sex of an individual. However, in 1949, Barr et al.1 described an extranucleolar chromatin mass or "satellite" as a histologic characteristic of the nervous system cells of female cats. Five years later Emery et al.2 reported that in the cells of the epidermis of living human subjects an extranucleolar chromatin mass was seen in greater than 25% of the cells in females and in less than 10% of the cells in males. A few months later Davidson et al.3 reported the presence of an extranuclear chromatin mass, or "drumstick," in the polymorphonuclear leukocytes of human females. With these advances came the opportunity for the early and accurate diagnosis of genetic sex in patients in which an abnormality in formation of the genital system had occurred.
The demonstration of hormone dysfunctions in a variety
COOPER KH, CRANNY RL. The Determination of Genetic Sex in ChildrenA Critical Evaluation of the Reliability of Polymorphonuclear Leukocyte Morphology. AMA Am J Dis Child. 1958;96(1):40–42. doi:10.1001/archpedi.1958.02060060042007
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