Who's the Model Mom?

Duh, it's Christy Turlington.

The mother of two and wife of Ed Burns took her daughter Grace out for a little Soho stroll yesterday....during a break from her textbook, that is.

Yep, Christy isn't your average catwalker.  The ex-super model is done with fashion and ready to do good for humanity. 

Starting this month, she'll complete a Master's program in maternal and child health...at the prestigious Columbia University, of all places.

Guess you can't just a model by it's long legs...