Sarah Michelle Gellar -- Good Genes or Good Docs?

Sarah Michelle Gellar's beauty is to die for!

Here's a 17-year-old version of the 'I Know What You Did Last Summer' scream queen at an event in NYC back in 1994 (left) and 24 years later ... The now 41-year-old mother of two was spotted showing off her scary good looks at a charity event earlier this year (right).

Looks that slay!

The question is ...