From a White House release:

Vice President Dick Cheney and his wife, Lynne Cheney, welcomed their sixth grandchild, Samuel David Cheney, Wednesday, May 23, 2007. He weighed 8 lbs., 6 oz and was born at 9:46 a.m. at Sibley Hospital in Washington, D.C. His parents are the Cheneys' daughter Mary, and her partner, Heather Poe. White House photo by David Bohrer