Prengnancy?

hi there its me again... heheh ladies here are some q for u gals. I am already 4 months now as you know hmm i am just curious can the doctor predict the gender of my baby at 3months ++ and can it be trusted.. 2nd question recently i have been craving for gas drinks last 2 nites i drank root beer and rite now i am drinking cherryade f&n but i don usually drink until the last drop but sumtimes the urge is there... Is it bad for my baby cause i will burp a lot of times after drinkin the drink.. heheh experts i need yur advises and if its bad how can i stop the craving for it .. i am just afraid that my cravings for worsen