Mary Cheney Gives Birth to Baby Boy By Amy Argetsinger and Roxanne Roberts Washington Post Staff Writers Wednesday, May 23, 2007; 5:36 PM Mary Cheney gave birth today to perhaps the most anticipated baby in contemporary U.S. politics -- her first child, Samuel David Cheney, whom she will raise with her longtime partner Heather Poe. The 8-pound, 6-ounce boy is the sixth grandchild for Dick Cheney.