Gavin Newsom and Jennifer Siebel's brand-new baby boy, Hunter Siebel Newsom, was born in San Francisco this morning at 9:18 a.m. He's 20.5 inches long and weighs 8 pounds 4 ounces.

Congratulations to Newsom, Siebel, and 20-month-old big sister, Montana.

(This contributor has an 18-month-old and can only imagine what it would be like raising two bundles of joy so close in age. They were probably smart to bang them out so quickly, though.)