Correct use of the comma.

The first one is the popular and "more" correct one. Over the years, the first has become much more dominant. I remember throughout Elementary school, I was taught the second way. However, by the time I was in High school, I began seeing the first method everywhere - and I promptly adopted it.

Though, like Isaac said, either is grammatically correct.

From my personal observations (mainly of my professors), I've noticed that all of the older ones use the second method, while the younger ones tend to use the first. Sign of the times, perhaps? It's weird that your parents have it backwards.