# In a two-child family, if one child is a boy, what is the probability that the other child is a girl? If the first child is a boy, what is the probability that the second is a girl?

Oct 22, 2015

50% for both questions
It should be noted that the male:female birth ratio is not really $50 : 50$ (it is slightly biased in favor male births; 1-2% if I recall correctly).