Yes, GERD can be genetic but it isn't always. Also, smoking and sodas are considered to make it worse.

Zantac is an acid reducer known as an H2 blocker. It slows down the production of the acid. In general the H2 blockers are considered to be not as strong as the Proton Pump Inhibitors such as Prevacid and such. But, if you can be adequately managed with an H2 blocker than you wouldn't necessarily want or need something stronger.

Burping is a sign of reflux. I have not heard of it being a symptom of the Zantac.

You can read more about reflux causes and treatments at:

http://www.healthcentral.com/acid-reflux/introduction-000085_2-145.html?ic=506019