Child stars: Where are they now?

73 of 80: Danica McKellar was about 12 years old when she began filming episodes of 'The Wonder Years.' She played Gwendolyn 'Winnie' Cooper - Kevin Arnold's childhood crush - on the show, which ran from 1988 to 1993.

Since then, McKellar earned her mathematics degree from UCLA and is a New York Times bestselling author and mathematician. She still acts and guest starred on 'The Big Bang Theory' in 2010. She and Apolo Anton Ohno also star in a 2013 SyFy film called 'Tasmanian Devils.'

(Pictured: Danica McKellar and Fred Savage appear in a scene from 'The Wonder Years' in 1988. / Danica McKellar talks to OnTheRedCarpet.com on Dec. 15, 2011 at a Los Angeles party to celebrate the 100th episode of CBS series 'The Big Bang Theory.') (New World Television / ABC / OTRC)