Answer
$\frac{1}{32}$
Work Step by Step
We know that $probability=\frac{\text{number of favourable outcomes}}{\text{number of all outcomes}}$
An event of a newborn being a boy is independent from the other births thus the probability is the probability of a boy being born raised to the power of $5$, which is: $(\frac{1}{2})^5=\frac{1}{32}$
