Originally Posted by Bostonian
To raise to 50% the chance that each child will have a sister (or in other words, to have two daughters), you need to have three children smile.

Every time a parent tells me they're going to have another child because they always wanted to have a [gender], I always get this image of them standing at a craps table, shaking the dice fiercely, and saying, "Come on, [gender]." Usually, followed by, "Doh!"