It basically gives you an 85% chance of having a girl. They do something with the sperm and basically try and get rid of all the Y sperm and then artificially inseminate you with the X sperm. I guess there just could be some Y sperm left and that's why it's not 100%.

I completely understand why you would want to have a girl. After all these girls we soooooo wanted to have a boy. We would of loved a little girl but WE REALLY wanted a boy....we didnt do anything though..we just left it up to the powers that be.