the presence or absence of sex chromatin in cells obtained by amniocentesis makes it possible to determine the sex of a fetus.
Examples of sex chromatin
sex chromatin
Micro scopic examination of carefully cultivated slides, they discovered, reveals the presence or absense of the sex-chromatin body that determines femininity.
From the time.com
A chromatin modifying enzyme helps compensate for the fact that males have only one copy of the sex chromosome X, while females have two.