Obviously, we are all not interested in hearing any more "now that I have a daughter, I know the value of women, since I'm now the proud owner of one, and you should be nice to them!" crap. This one, entitled "Stop Asking If I Am Going To Try For A Boy," pleases me greatly.
I have a few friends who only have daughters, and the joke is always that Dad is outnumbered, or Dad will be protective, and I have definitely heard "time to try for a son" a few times (I imagine if I were actually a parent, I would hear this more).
The problem is that, in assuming that I can't possibly be satisfied with having daughters, you are perpetuating the ancient and awful tradition of preferring boys to the detriment of girls, and you are devaluing my daughters. Please stop it!