Definition: The sex chromosome found only in males. The two types of sex chromosomes, X and Y, determine the sex of an embryo. Women have two X chromosomes and men have an X and a Y chromosome. Because of this, the sex of the child is determined by which chromosome the male passes down. At approximately the eighth week of prenatal development, the Y-chromosome triggers the development of male sex organs.
Y Chromosome
By Kendra Van Wagner, About.com
Explore Psychology
Must Reads
About.com Special Features
Make Meals Easy
An easy way to put delicious meals together.Build Your Business
Get tips on starting up and staying competitive.Love Your Living Space
Achieve your dream home with advice from the pros.Financial Planning
Stay on top with our smart financial tips.
©2009 About.com, a part of The New York Times Company.
All rights reserved.