Kim Kardashian & Mason's Most Precious Moments

She's a natural! See the mom-to-be showing off her maternal instinct with her sweet nephew

SO HIP

In between riding trains and hanging with mom Kourtney and dad Scott Disick, a dapper Mason (check out that slicked-down hair!) spends some quality time with his doting aunt Kim at his 1st birthday party on Dec. 12, 2010.