Rant!!!!

I am 20 weeks and we are choosing NOT to find out the gender of our baby (this is something I have said I was going to do my entire life) so when people naturally ask what we are having, I simply respond with something along the lines of "we will find out in July" or "we are not finding out" but the response I get from people (both family and friends) is just so rude!! It makes me so mad! I get weird looks and comments like "that's so dumb/stupid" "why would you not want to know" "well how are you going to be prepared for the baby if you don't know" and so on... I don't question other people on why they want to find out nor do I find it odd that people do want to find out!! I am at the point to where I want some sort of response that will make them feel 2 feet tall for being so rude but I just don't know how to be rude to people! What do you think? How would you respond?