How might I get a copy of my deceased parent and grandparents US birth certificates?

http://dph.georgia.gov/VitalRecords

Good for Maxi (and the state vital records office is a basic).

I'll add a note... you didn't include dates, which can be important. Georgia enacted laws for birth certs in 1919. Often, it takes a few years before all the folks get the message so you could have "not found", if right in that time frame. Over here in this area, we don't assume anything, so your parents may have been born back that far (my mom was born in 1909).

You go to court wit an attorney , i think