In human beings,the statistical probability of getting either a male or female child is $50 : 50$. Give a suitable explanation.

(N/A) The sex of an infant is determined by the type of sex chromosome contributed by the male gamete. Human males produce two types of gametes: $50\%$ containing the $X$ chromosome and $50\%$ containing the $Y$ chromosome. When a sperm carrying the $X$ chromosome fertilizes an egg,the resulting zygote develops into a female $(XX)$. When a sperm carrying the $Y$ chromosome fertilizes an egg,the resulting zygote develops into a male $(XY)$. Since there is an equal chance of either an $X$-carrying or $Y$-carrying sperm fertilizing the egg,the statistical probability of having a male or female child is $50 : 50$.