Happy Father's Day to Bill Clinton, Marc Mezvinsky, and all the Dads (... and Single Moms Doing Dad-Duty)!

Bill Clinton and Marc Mezvinsky could not have had a better Father's Day gift!

Chelsea Clinton ‏@ChelseaClinton 

At 7:41 AM Saturday, our family and hearts expanded with Aidan’s arrival. We are blessed.

Hillary Clinton ‏@HillaryClinton 

What a joy being with our new grandson, Aidan. So grateful. -H

Bill Clinton ‏@billclinton 

Aidan has made two dads very happy this Father's Day. Hillary and I are thrilled for Marc and Chelsea!

Hope all the dads are having an excellent day, and that includes all surrogates: granddads, uncles, big brothers, and everyone else who doubles as a dad.