A-positive
A-positive was a very common blood type on Earth.
In Nazi Germany, all members of the Schutzstaffel, which was meant to be an Aryan organisation, initially had to have A-positive blood. (AUDIO: The Dying Room [+]Loading...["The Dying Room (audio story)"])
As of 25 December 2006, about one-third of Earth's population had A-positive blood, including the British Royal Family, Sally Jacobs, Luke Parsons, Geoffrey Baxter, Jason Overton, Alan, Catrin and Jonathan. The Sycorax used this to their advantage in their attempted invasion of the world by using blood control on all the A-positives using a vial of A-positive blood donated by Duerte Rodriguez placed on the Guinevere One space probe. (TV: The Christmas Invasion [+]Loading...["The Christmas Invasion (TV story)"], PROSE: The Christmas Invasion [+]Loading...["The Christmas Invasion (novelisation)"])