Alison Docherty's son
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Alison Docherty had a son. When the Toclafane attacked Earth in 2008, Alison worried that he may have been among the casualties.
During the Year That Never Was, Alison was still unsure if her son was alive. Desperate for information, Alison betrayed Martha Jones and revealed her plan to the Saxon Master in exchange for information regarding her son. (TV: Last of the Time Lords)