I believe its personal preference but can never understand why ppl who do find out (like me) are put down for it... Like its such an awful god forbidden thing so if you do find out just be weary of those comments and ppl looking at you like you've just commited a crime by finding out.
The only ppl that can really say what its like are those that have had one baby and found out the sex and then gone on not to...
For me personally I found out, and im so glad I did, yes we did buy lots of blue stuff and his room will have lots of blue but thats not why I found out, for me finding out was like a progression in pregnancy, I can refer to baby as HE and I don't feel like i've spoilt any type of surprise... i didnt walk out the scan room thinking oh no i know now, this pregnancy is gonna be a right drag from here on...
Ppl go on and on about this "Surprise" the surprise isn't finally knowing your baby will be male or female, to me the surprise is what my baby will look like, how his hair will be, what music he will grow up to like, his first words the list is endless to me that is the surprise...
Whether or not you find out is up to you but don't allow anyone to sway whether its right or not to do so...