Penelope Cruz: Good Genes or Good Docs?

Penelope is Cruz-in' through aging well!

Here’s a 25-year-old version of the sexy Spaniard at a premiere in Los Angeles back in 1999 (left) and 18 years later ... when the mom of two celebrated her 43rd birthday -- at a charity event in Madrid earlier this week (right).

Ay mami!

The question is...