Confused about gelato vs. ice cream

I was sure I knew that gelato had eggs in it - but while visiting an ice cream shop in MA the guy behind the counter (Well, I must say he was young) told me that no, there were no eggs in the gelato. But I was so SURE that gelato was loaded with yolks.

Then I'm watching FoodTV and Giada not only puts yolks in her gelato she then says that gelato is different from ice cream because gelato uses both cream and milk (I rewound to make sure I heard her correctly).

WHAT? So does EVERY ice cream recipe I have. Yolks, milk and cream - that's ice cream. Is that also gelato?

Anyone know the final word on this?