OMG Jacci... I cant believe he wouldnt let you find out the sex!! I have never heard of that happening before...

That is silly for him to say that finding out the sex at the scan is a cause of postnatal depression.. if anything it would give the mother/father time to get used to the sex of their baby and come to terms with before the birth...

I would be very angry if I were in your shoes... and would probably complain and demand another U/S, with a different sonographer, free of charge.
Although, I have no idea if its within the sonographers rights to refuse to tell the sex or not?