Christina Velasquez was a 23rd century Human female. By the late 2250s, Velasquez was a lieutenant serving in Starfleet, assigned as chief medical officer aboard the USS Constitution. In 2257, Velasquez joined the Constitution's senior staff in a small gathering in the ship's lounge as they welcomed aboard new helmsman and second officer, James T. Kirk. A short time later, Velasquez spoke to Kirk about Chief of Security Jack Gaynor following an altercation in the rec room. (TOS - My Brother's Keeper novel: Constitution)