EMINEM GOOD GENES OR GOOD DOCS?

10/18/2015 12:20 AM PDT

Eminem: Good Genes or Good Docs?!

Eminem's looks don't need a remix.

Here's a 27-year-old version of the Slim Shady songbird looking serious in Dublin back in 1999 (left) and 16 years later ... the "Rap God" -- who is celebrating his 43rd birthday this weekend -- looking even more serious at an NYC movie last summer (right).

Berzerk.

The question is ...