Unnatural Selection ( episode ) The " Enterprise " investigates the deaths of the crew of the USS " Lantree " , who all died of old age . Summary . Teaser . En route to the station , Captain Jean - Luc Picard asks Counselor Deanna Troi about his new chief medical officer , Katherine Pulaski . He has concerns about her dedication interfering with her objectivity . She senses his concerns , but believes she is a good choice for chief medical officer . Data then receives a distress signal from the Federation supply ship . All they say is that they are dying , unable to give any more details . The voice on the other end of the comm is weak , and then falls silent . Act One . When the " Enterprise " arrives and hails the ship , there is no answer . Data reads no life sign s , but all systems seem functional . At Commander William T . Riker ' s suggestion , the " Enterprise " establishes a remote link with the " Lantree " s computer . Picard quickly goes to his ready room to provide access codes to authorize the link . When they turn on the bridge monitor , the entire crew is dead . Dr . Pulaski ' s scans find they died of natural causes through aging . In the conference lounge , everything is laid out on the table . They download and play back Captain Telaka ' s last entry : Riker says that Captain Telaka was his age . The Doctor ' s search of medical records indicate nothing happened , except that the first officer was treated for the Thelusian flu at Darwin Genetic Research Station on the planet Gagarin IV . She has the ship quarantine d , and they head for Gagarin IV . Act Two . Once in orbit , they hail the station . Doctor Sara Kingsley answers , and explains they have declared a medical emergency . Their staff is suffering from the same phenomenon as the " Lantree " . She is convinced they were infected by the crew of the " Lantree " . She wants " Enterprise " to help them evacuate their genetically - engineered children to protect them . Doctor Pulaski says there must be a full quarantine on the station , and that includes them . But Doctor Kingsley pleads that the children have no symptoms . The captain interrupts and says there is very little they can do , they will discuss it . In the conference lounge , Doctor Pulaski says that the children should be evacuated after a full examination in a force field . Picard decides that they must err on the side of caution , and denies her permission for the examination . If they are carriers , the ship could quickly become infected . The doctor instead suggests she beam up a child encased in styrolite , in suspended animation , so she can scan for disease without it being able to spread . She doesn ' t know what to scan for , and the only way to know is to collect some data . Chief Engineer Geordi La Forge sets up the force field , and the twelve - year - old child is beamed aboard by Chief O ' Brien . However , what materializes is a male whose age is closer to twenty . Worf is about to call it a trick , but Picard stops him from doing anything rash . Since the styrolite is intact , he orders the force field down , and lets the doctor scan him . Counselor Troi immediately detects a strong presence , even in stasis . She believes he is telepathic , a surprise to everyone . Act Three . After scanning with everything they ' ve got , the doctor concludes ecstatically that he is in better health than the crew . In fact , his immune system is so advanced , it may not be possible for him to contract disease . She wants to release him to do further tests . Picard won ' t allow that . Despite her passionate opinion and interrupting the captain a few times , the risk is too great . She tries to think of everything , suggesting force fields and separate environmental systems , but the captain knows they can fail , and to him , that is not acceptable . The best he can give her is an open door : if she can find a way which is more accident - proof , bring it to him , and he ' ll allow it . Picard then informs Pulaski that he is not one to discourage input but asks her to let him finish his sentences once in a while . When she talks to La Forge , he suggests the only independent environment is a shuttlecraft . When she takes her suggestion to Picard , he doesn ' t like it , since she would still be at risk . But as she is about to argue , he immediately approves her request , much to her surprise . She takes Data to pilot the " Sakharov " , and has the boy beamed aboard . She removes the styrolite , and immediately , he comes to life . She is surprised when he suddenly reaches out to her telepathically . For eighteen minutes , she examines him , and when Data confirms that everything seems to be fine with her , she suddenly gets an arthritic cramp , the first stage of the disease . Act Four . Still startled , in pain and very agitated , she tells them to return the boy to Darwin station , and says there is nothing they can do for her . She will not make herself an exception to the quarantine . Since she is now suffering from the same disease as the Darwin staff , she decides to head to the station . When the rest of the senior staff meets in the conference lounge , they don ' t see what they can do for her . The children are carriers , and they can ' t screen out the disease because the boy was beamed twice already and he still had it . However , Transporter Chief O ' Brien gets an idea : they can use the transporter trace trace , a previous pattern when she didn ' t have the disease , to control the way she is reconstituted . Unfortunately , no one remembers her ever using the transporters ; she possesses transporter phobia . Picard asks for the captain of her last assignment , the , to be contacted via a captain ' s priority subspace message . Aboard the station , the puzzled Kingsley still cannot believe it is the children who transmit the disease . She shows Data and Pulaski several telekinetic children , their finest achievement . These children , she proudly argues , are perfect in every way . In fact , their immune system is aggressive , creating an antibody to destroy the virus in midair by altering its genetic code . It even works at a distance . That ' s when the light bulb goes on in Pulaski ' s mind ; remembering that the " Lantree " ' s first officer was suffering from Thelusian flu when he visited the station , she tells Data to run a genetic analysis on the interaction between the flu virus and the antigen . Kingsley remarks that such an analysis could take months ; Pulaski informs her that Data has a way with computers . Back aboard " Enterprise " , Captain said they erased her pattern after she transferred , not that she used the transporter much , preferring to take shuttles . Taggert says he would have given Pulaski a shuttle if it kept her on the " Repulse " , however the moment she saw there was an opening on " Enterprise " , she jumped at it , because she greatly admired Picard . Data ' s analysis is conclusive , and unfortunate . As he explains to the astonished Kingsley and Pulaski , the antibody the children created to counteract the virus interacts with normal Human DNA to change sequences which affect the aging process . The children are in fact more than carriers ; they ' re the " cause " . Since DNA is self - replicating , the effects are irreversible . Act Five . Devastated , the two desperate women lose all hope and recognize defeat . Pulaski sadly and silently accepts her doomed fate , while Kingsley tries in vain to get a hold of herself , but can´t help but ending up crying . Looking tired , Pulaski explains the situation to Picard through the viewscreen . She looks at least twenty years older , and in pain , but trying her best to look strong . He wishes to beam her aboard in suspended animation and keep her until they can repair this damage , but she is adamant against it . She doesn ' t want them to leap before they looked like she did . Instead , she reads a log entry over the com : Data beams back aboard after a farewell to the now - white - haired Pulaski , who looks around a hundred years old by now , like the equally deteriorated Kingsley . Both women now seem to have accepted their terrible fate with more calm by now , but both still look very depressed . However , after Data is screened for organics and beamed aboard , Picard asks him about another idea . Since the genetic changes are the cause , they could take a sample of her genetic code and have the transporter reverse the transposition . Chief O ' Brien says it will work , but it would be risky , since they will lose her pattern if it doesn ' t work . It takes some doing to get a DNA sample ; Pulaski ' s records have not arrived from Starfleet Command yet . Riker and Data search her quarters and finally find a hair follicle on her hairbrush . Picard calls Pulaski . The bridge crew and Picard are shocked by the image of severe deterioration , now looking much older than a hundred years . The captain explains the possible solution to the terminal doctor . Pulaski , now totally exhausted , out of time and options , is willing to give it a try . Troi is very shaken and sad , seeing and possibly feeling Pulaski ' s terror , despair and unbearable suffering . O ' Brien warns Picard that the trip is one - way only ; if the procedure doesn ' t work , Pulaski can ' t be beamed back to Darwin Station . Picard takes the transporter controls and assumes full responsibility for the attempt so that O ' Brien will not be to blame should something go wrong , to O ' Brien ' s gratitude . After a tense several seconds of controlling the transporter during beam - in , the doctor , restored to her proper age , appears . Picard admits to her had the procedure not worked he would have had to beam her pattern into space . Pulaski doesn ' t mind , since she assumes the worst whenever she uses it anyway . The " Enterprise " returns to the USS " Lantree " and , after paying final respects , consigns the ship to oblivion by destroying it with a single photon torpedo . Memorable quotes . " " Commander , I want an analysis of the interaction between the Thelusian flu and the children . " " " " On a molecular genetic level ? " " " " We don ' t have time for that ! Genetic analysis could take months ! " " " " Not necessarily . Commander Data has a way with computers . " " " " Looks like they had a battle with time … " " " " … and lost . " " " " Extreme caution . The USS " Lantree " is a quarantined vessel by order of Starfleet Command . Do not board . " " " " What is your condition , doctor ? " " " " Not exactly up to factory specs . " " " " What if we used a sample of her DNA , say , from a blood test taken before she was exposed to the disease . Could that be used to filter out the genetic changes ? " " " " Well , I ' d have to get into the biofilter bus and patch in a molecular matrix reader . That ' s no problem . But the wave form modulator will be overloaded without the regeneration limiter in the first stage circuit . " " " " Interesting . However , theoretically – " " " " Data . " " " " Apparently , she ' s been an admirer of yours for some time . " " " Extraordinary . " " " Doctor , God knows I ' m not one to discourage input , but I would appreciate it if you ' d let me finish my sentences once in a while . " " " " If this hadn ' t worked , it would have been necessary to beam your energy into empty space … " " " " … and spread my atoms across the galaxy ! " " " " Yes , I ' m sorry , it … " " " " No , no , don ' t be sorry . Every time I get into the damn thing I ' m convinced that ' s what ' s going to happen . " " " " Chief Medical Officer ' s Log , this will be my final report to the " Enterprise " . Just as changes in evolution are known to be caused by changes in the environment , we now know the process also works in reverse . An attempt to control Human evolution has resulted in a new species , which is lethal to its predecessors . The children will be condemned to live out their lives in isolation . The quarantine of the Darwin Station must be maintained forever . " " Links and references . References . 2330 ; 2335 ; 2353 ; 2365 ; adenine ; antibody ; arthritis ; bedside manner ; biofilter ; chromosome ; Class 6 Federation supply ship ; cytosine ; courier ; Darwin Genetic Research Station ; Denkir IV ; DNA ; evolution ; Federation ; Gamma 7 sector ; Gagarin IV ; genetic analysis ; genetic research facility ; guanine ; hair follicle ; immunity ; kilometer ; ; Lantree first officer ; Linear Models of Viral Propagation " ; liver ; lung s ; marker beacon ; medical scan ; meter ; microscope ; Milky Way Galaxy ; milliparsec s ; molecular transposition ; NCC - 7100 ; number one ; parallel course ; parsec ; pathology ; quarantine ; quarantine transmitter ; ; " Sakharov " ; security access code ; Shuttlebay 3 ; Starfleet Academy ; Starfleet Medical ; Star Station India ; styrolite ; subspace frequency ; supply ship ; telekinesis ; Thelusian flu ; thymine ; tissue sample ; tour of duty ; transporter ; transporter ID trace ; transporter log ; Type 7 shuttlecraft Unused production references . Astarte ; Gagarin system