RuPaul -- Good Genes or Good Docs?!

Aging for RuPaul Charles is anything but a drag!

Here is the 39-year-old version of the "Supermodel (You Better Work)" singer at the ASCAP Awards in Beverly Hills back in 1999 (left).

And, 20 years later ... the now famous drag queen and host of "RuPaul's Drag Race" -- who is celebrating his 59th birthday Sunday -- workin' some specs after sashaying away with a win from the 71st Emmy Awards in Los Angeles last month (right).

If you can't love yourself, how in the hell you gonna love somebody else? Can I get an amen?

The question is ...