I think it really depends on how you will handle the news. I had severe GD with DS#2 because I was expecting him to be a girl (becuase I tried to read but misread the u/s and then just assumed it was a girl)-if I had actually found out -I imagine I would have been dissapointed but then could have prepared myself instead of dealing with the hormones of PPD that were aggravated by GD. If you are prepared for and able to welcome either gender easily then I say wait, it's a lot of fun to get the d]surprise!