Leslie Mann GOOD GENES OR GOOD DOCS?

0328_leslie_mann_good_genes_launchLeslie Mann she looks good!

Here's the then 24-year-old "Cable Guy" babe at a premiere in Los Angeles back in 1996 (left) and 18 years later, the now 42-year-old mother of two at a movie conference in Las Vegas earlier this year (right).

"This is 20?"

The question is...