Boy or Girl Explained
The “Boy or Girl Paradox” (also called “The Two Child Problem” in addition to other names) is generally phrased as follows:
You know a couple who has two children. At least one of the children is a girl. What is the probability that they have two girls?
This is an ambiguous problem, which leads to different answers depending on the assumptions that are used. Not enough information has been provided to produce a definite answer, and the unstated assumptions fill in the space needed to complete the logic.
Here I investigate this problem and explain the ambiguity.