Page 77 - The Miracle of Human Creation

(a) normal human male chromosomes

sex chromosomes sex chromosomes
of father of mother

meiosis
possible possible ova
sperm types types

possible
genotypes of
zygotes
(in boxes)

possible phenotypes
of offspring
females males

(b) sex determination

The sex of a baby depends on which male chromosome unites with the female egg. Of the 23
pairs of chromosomes (that is, 46 individual chromosomes), 2 are called sex chromosomes.
These two chromosomes are designated as XY in the male and XX in the female. The Y chro-
mosome carries male genes, the X chromosome, female genes. The formation of a human body
begins with the union of one of each of these chromosomes, which are present in pairs in males
and females (left). If the X chromosome in the female unites with the sperm containing the X
chromosome in the male, the baby will be a girl; if it unites with the sperm containing the Y chro-
mosome in the male, the baby will be a boy. (Gerard J. Tortora, Introduction to the Human Body: Essentials
of Anatomy & Physiology, pp. 569-570)

among the evidence of this fact.
It is a Book We have sent down to you, full of blessing, so let people of intel-
ligence ponder its Signs and take heed. (Qur'an, 38: 29)