A woman has two kids. One is a boy. What are the odds the other is a boy?

Let me try the example I gave on irc.

First I gave the coin example.

And then I said "Okay, a woman has a child. It is a boy!"
Then I said "She's about to have another one. What is the chance that the new child she has is a boy?"

So, answer my question

that's 50%. But that's not the question here