J.Lo reveals her beauty secrets; our dermatologist weighs in

She's a 46-year-old mother of two, yet 20 year olds might envy her look. Jennifer Lopez is now revealing what she does and doesn't do to stay looking young and fresh.
  
The mother of 7-year-old twins tells US Weekly she avoids booze, caffeine, the sun and cigarettes, and that she eats plenty of greens, meditates daily and gets about 8 hours of sleep nightly.

  So has she discovered the fountain of youth? Or is it good genes?

Dermatologist Steve Grekin explains how many factors contribute to aging.