Just caught the pilot episode, and Dorothy referred to Stan as 'a 65-year-old man with gout'. Aren't they supposed to be the same age? That would have made Dorothy 65 when the show started, which is highly unlikely. It also means Sophia had her when she was 15, because she's 80! And Dorothy also says she was married 38 years, which would mean they would have been broken up almost a decade by the time of the pilot.
When the show became a hit, all this stuff evolved over the seven seasons. And, of course, they had no way of knowing that us fans would be here picking it all apart going on 40 years later!