In human beings, the statistical probability of getting either a male or a female child is 50%. Give reasons and explain with the help of a diagram.

Explanation

The sex of an unborn child is determined by the type of sex chromosome contributed by the male gamete. Male sex chromosomes are heterozygous (XY). Hence during gamete formation, 50% of the gametes formed have X chromosomes and the other 50% have Y chromosome. Since the ratio of male gametes containing X chromosome and those containing Y chromosome is 50:50, the statistical probability of male or a female infant is also 50: 50.