I am careful in my wording, but my two oldest are nearly 11 and 14 and are pretty mature. We have a good sense of humor in our house and a very open line of communication so yes, my girls know that although we would have loved to have had a boy, BUT we are more than thrilled to have ended up having all girls and what a treat it has been to raise them and see them have each other as sisters. They are very close and don't seem to display even subtle hints that they think this means we are disappointed in them in any way. Also, we are a Christian household that truly believes in fate and that God gives us what is planned and meant for us and they get that too. I think our joking with our kids about societal pressure to things like having a pigoen pair helps them understand the world. Kids aren't oblivious to the comments right in front of them from strangers such as, "Oh, you must be trying for a boy (when we were pregnant with out third daughter)" or the like. It helps broach other topics like peer pressure even and other's expectations projected upon us and talk more about them.