Realized I didn't really complete my thought and didn't bother to register so I could edit...so here is the rest.

So of the two scenarios which should one assume matches the original question that Lorinda posed. This is more subjective question. But the key to me is whether or not the friend was "free" to say "One of my friends children is a girl" even if one was a boy. Since no restrictions were given on what she possibly could have said, if I must bet solely on the information given, I would go with the assumption that the 1 in 2 scenario matches most closely.