There’s a google interview question that’s been discussed quite a bit in various forums recently. The question is: There is a certain country where everybody has to have a son. Therefore each couple keeps having children until they have a boy, then they stop. In expectation, what fraction of births are female? Apparently the “official google answer” is 0.5 due to the fact that the expectation of each birth being a girl (or boy) is always 0.5. The “stopping rule” does not change this expectation. The controversy is that some say that the official google answer and argument are wrong. Any comments?