Congratulations! And, good luck! My wife gave birth to identical twin girls very recently. And let me tell you that if you think it'll only be twice as tough as a single baby, you are wrong. I'm pretty sure your pie-chart is still valid for twins though - it is just a bigger personal investment for a bigger final reward. Well, that's what I keep telling myself. Just imagine all the fun experiments now that you have potential for a control sample ;-)