Is It Offensive to Call a Redhead a ‘Ginger’?

It's well-known that Cefus loves the ladies, especially if they are blond. Rik mentioned brunettes and then referenced redheads as "gingers" this morning on air.

Cefus and I mentioned that we don't think redheads like to be called "gingers," that it's derogatory.

If you're a redhead are you offended by being called a "ginger"?