I have only found out with this baby, never with any of my others. My reasoning was that if I am to have a boy, I really need to start shopping for boy clothes. At the morphology scan we asked to find out the gender and the baby was in a difficult position as well as the cord being in the way, so we didn't get a definite answer. We asked again at the 3d/4d scan and it was pretty much the same thing. I had a growth scan done at 32 weeks where we could see more clearly but in my mind I am not 100% sure so I have not bought anything in pink or blue... I've bought some of each!
I have 15 days to go and I figure I will find out then! I love shopping after the bub arrives.