I don't think one of you can know without the other.

It is such a personal decision. For me, no way did I want to know. I love the surprise at the end. DH wasn't sure if he wanted to know the first time and did want to know the second time, but went along with what I wanted so we didn't find out either time. The first time I had a feeling all along it was a boy, so it wasn't a huge surprise. Second time I had no clue and it was a wonderful surprise to hear "it's got boy bits" LOL!