Family of Blood The Family of Blood were a family of hunters who hunted the Tenth Doctor in order to take his near - immortality . Biology . The Family of Blood were green , gaseous predators that could inhabit and control human bodies . Before taking human form , the members of the Family of Blood were kept in small , spherical receptacles . They had very short lifespans , and , if they went without possessing anyone , they would perish in just three months , " like mayflies . " ( TV : " Human Nature " ) The members that were chasing the Doctor consisted of a father ( Father of Mine ) , mother ( Mother of Mine ) , son ( Son of Mine ) and daughter ( Daughter of Mine ) . While in human form , the Family could telepathically communicate with each other from a distance . They always referred to each other by their relationship followed by " of Mine " , i . e . Father ( or Husband ) of Mine , Mother ( or Wife ) of Mine , Son ( or Brother ) of Mine and Daughter ( or Sister ) of Mine . Father of Mine referred to Mother of Mine as " Wife of Mine " when reporting that he had found the Tenth Doctor ' s TARDIS , indicating that the two were in fact married ( or their equivalent of such ) . They also had an incredible sense of smell , tracking the Doctor wherever the TARDIS took him by his scent alone . Unfortunately , whenever they possessed someone , their victims ' minds and memories were mostly obliterated ; the remaining knowledge was barely sufficient for the Family to successfully pose as their victims without arousing suspicion . ( TV : " Human Nature " / " The Family of Blood " ) Technology . The Family utilised a spacecraft , that held their ' essence ' within it prior to them assuming human form . The interior contained green lights , pillars and paddle - like switches ( somewhat similar to the Doctor ' s TARDIS ) and seaweed - like plants dangling from the ceiling . The spacecraft had a considerable arsenal of technology — the most notable of which was a Vortex Manipulator ( stolen from the Time Agents ) that allowed the craft to travel through time . It could also project force fields , render itself invisible and had bomb - shooting cannons . On hand , the Family of Blood used energy guns that fired green energy that disintegrated humanoid tissue — the weapons apparently consist of a living creature within a shell that shot the beam when pierced by the trigger . They were somewhat difficult for humanoids to hold . The Family also had scarecrow - like soldiers created by Son of Mine and placed in various fields . They were composed of straw , their molecules animated via a scientific process . Even after being shot down , they could still reanimate by the command of the Family . ( TV : " Human Nature " / " The Family of Blood " ) History . The Family encountered the Tenth Doctor and Martha Jones , and chased them throughout time and space with a stolen Time Agent vortex manipulator , hoping to steal from the Doctor some means of ensuring that they would live a longer lifespan . According to Son of Mine , on the Family ' s travels through time and space in search of the Doctor , they saw many things , including the First World War . The Doctor was forced to turn himself into a human using the Chameleon Arch in his TARDIS in order to escape them . The Doctor changed himself into John Smith , a teacher at a boy ' s school in England in 1913 . The Family eventually came there and landed nearby , and activated animated scarecrows to round up humans to possess as bodies . ( TV : " Human Nature " ) The Family ' s quests for immortality ended when the Doctor was returned to his Time Lord state with the help of Martha , school nurse Joan Redfern and Tim Latimer . He fooled the Family by pretending to still be John Smith and using an olfactory misdirection ( said to be like " ventriloquism of the nose " ) to trick them into thinking that he was still human . Moments later , an act devised to look like a clumsy accident by " John Smith " resulted in the Family ' s ship overheating and exploding . The Doctor subsequently punished the Family by : In a sense , the Family ' s quest for immortality was won , although not in the manner they wished . They also discovered from this why the Doctor decided to flee rather than fight them — he was showing them mercy , by allowing them the chance to live out their lives then die , rather than killing them or dooming them with immortality . ( TV : " The Family of Blood " ) Behind the scenes . " The Visual Dictionary " . The source " " gave further information about the Family of Blood . Their telepathic communication means that when in very high trauma , others can feel this pain . When taking over human bodies , the Family ' s gaseous form enters them through the eyes .