lateral thinking - A man is born in 1955

(I heard this in a movie and I think it’s pretty cool.)

A man is born in 1955. Today, the 14th of August, 2017, he is 18. How is this possible?

Answer

The answer is simply:

1955 is where he was born. So either hospital room number or home address if home birth!

I have heard this one before but I don't remember where, maybe the movie you mentioned.