XY XY: The most frequent sex chromosome complement in
human males....
Xylitol Xylitol: A sweetener found in plants that is used as a
substitute for sugar. Xylitol is considered a nutritive sweetener
because it provides calories, just like sugar. (Saccharin is an
example of a nonnutritive sweetener, one that has no calories.)...
XYY XYY: An extra Y chromosome in a male. See: XYY syndrome....
XYY syndrome XYY syndrome: A chromosomal disorder that affects
males only, caused by the presence of an extra Y
chromosome. Symptoms may include increased height, speech
delays, learning disabilities, mild to moderate mental
retardation, and behavioral disturbance. Also known as
polysomy Y syndrome....
XXY