It's a topic that's come up a lot lately on KEEL's Robert and Erin morning show. It started with a news story about the "elopement" of actor Dennis Quaid, who's 66 and his fiance, actress Laura Savoie, who's 39 years younger.

From there the conversation turned to the age old "gentlemen's rule of thumb," i.e., what are the age limitations - if any - that should exist in a relationship. According to this rule-of-thumb, no man should date, much less marry, any woman who is younger than half his age, plus seven. In Quaid's case, for example, half of his 66 would be 33, plus seven. So, according to the bounds of propriety, the youngest woman Quaid should see romantically should be no younger that 40...and number that the new Mrs. Quaid misses by more than a decade.

So, we started to look around, to do a bit of research to find the best known celebrities who are involved in what is mythically known as the May - December romance and believe us, there are quite a few!