Question

A couple has six daughters. What is the probability of them having a girl child next time?

• A. 1/2
• B. 1/10
• C. 1/4
• D. 1/6

Answer 1

The correct option is A 1/2

The probability of a couple having a girl or a boy child will be equal i.e., 50%. There is an equal probability of fusion of an egg with an X-type to sperm with either X or Y type, irrespective of the number of children they had previously.
Finding out the possible genotypes of the progenies by Punnett square
$\begin{array}{cc}\text{Gametes}& \text{X(female gamete)}\\ \text{X (male gamete)}& \text{XX (daughter)}\\ \text{Y (male gamete)}& \text{XY(son)}\end{array}$
The ratio of XX: XY is found to be 1:1(50% each). Thus, the previous children’s gender can’t decide the gender of the next child.