NO, I really wanted to and DH stopped me, both times. Was totally shocked that Ds1 was a boy, was sure he was a girl.
My ex-boss knew the sex, named the baby in utero so when said baby was born, it was rather an anticlimax.
Trust me, you'll be pleased whatever and it is nice to be surprised (and I am exactly the same re: christmas/birthday presents etc, I hate surprises.)