For me, I grew up with a very simple image of finding out the sex on the arrival of the baby, it was just how things were done, I don't really know where I got that image from, I remember a teacher at school having a baby, when I was about 8 and her knowing it was a girl, so I don't think that visual of birth can really have been strongly formed prior to the knowledge that finding out the sex was possible.
I remember debating with my DH about it when we were engaged, one of the things I said then, and hold to know is I wouldn't want to find out the sex, for fear of spoiling that moment when you find out after giving birth. He was all for finding out, but then having seen how he responds if he is aware a surprise is coming up, it's no longer wierd to me that he would feel like that.
Thankfully, I think he was able to understand where I was coming from and has respected that, just like at Christmas, he will try and wrap presents in such away that I couldn't guess easily, even though I generally have to provide a list!
He has never put any pressure on me during pregnancy to find out, our first pregnancy we had routine scans, by the time or our second we'd decided on no scans without medical reason, we ended up having reason, but were in Korea at the time where it is illegal to tell the parents the sex of the baby, though apparently they will usually tell westerners, so we have a bit of a debate going on as to whether what I heard as femur and he heard as female was the tech telling us without thinking to ask, or whether she was simply point out the femur to us. This time around we've not had anything crop up to make us require a scan and the is the first pregnancy I've started to wonder if actually it would be preferable to know the sex and DH is very good at reminding me that there is no medical reason to scan and that if I was making this decision minus crazy hormones I'd be very quick to say that I dislike scanning for purely social reasons!