What it says really. When you start to go 3+ did you have really specific desires for a certain gender? It's just I have 2, a girl then a boy. Everyone keeps saying "ooh one of each so lucky" but I'd be happy to have another baby.... If I knew they would be a girl 
I have no idea at all why I feel this way and obviously I could never garuntee it. How did you feel about genders moving into a bigger family (especially if you already have both)? Obviously health is all that really matters, but let's face it sometimes you really really want a certain gender.