Molly O ' Brien Molly O ' Brien was the Human daughter of Keiko and Miles O ' Brien . Birth and life on the " Enterprise " . Molly was born aboard the in 2368 ( around stardate 45156 . 1 ) . Because the " Enterprise " was struck by quantum filament s that rendered various parts of the ship inaccessible to the rest of the crew , Keiko was trapped in the ship ' s Ten Forward lounge when she went into labor , and Molly was delivered by Worf . The O ' Briens seemed to have been preparing for the birth of a boy , which made the female child a surprise . ( ) As a baby , Molly was said to be the spitting image of her father . ( ) Later that year , Molly , together with her mother Keiko , was one of the crewmembers taken hostage by Ux - Mal criminals that had taken over the bodies of Data , Deanna Troi and her father , Miles O ' Brien . Molly didn ' t stop crying and so caused some tension amongst the kidnappers . When the kidnappers left Ten Forward with some of the hostages , including Keiko , she asked the kidnappers for permission to leave Molly in the care of Diana Giddings . The family was later re - united in sickbay after Miles O ' Brien had been freed from the influence of the alien s . ( ) In 2369 , Keiko , visited the planet Marlonia where she found a specimen of " Draebidium calimus " , which she brought back to the " Enterprise " on her return trip . Moments before docking on the " Enterprise " , their shuttlecraft , " Fermi " , became enveloped in an energy field , and their subsequent emergency transport caused her body to be changed into a twelve year old . While Keiko ' s body was still older and larger than Molly , the difference was noticeably less , and Molly had trouble adjusting to this change , refusing to acknowledge Keiko as her mother . This noticeably upset Keiko and probably motivated her decision to assume her previous age , so that she would be accepted as a mother to her again . She was eventually returned to her normal state and was accepted as a mother by Molly again . ( ) On Deep Space 9 . Later that year , Molly moved aboard Deep Space 9 , as her father got a new assignment there . ( ) Miles often told Molly bedtime stories . One of her favorites was " Rumpelstiltskin " . However , later Rumpelstiltskin appeared in Molly ' s room and wreaked havoc on the station until the crew realized he was a figment of their imagination . Before being defeated , Rumpelstiltskin offered to save the station in exchange for Molly . Miles was reluctant , but then the crew made a breakthrough and the O ' Briens were allowed to keep their daughter . ( ) Later that year , when Kai Opaka visited the station and came in contact with Miles O ' Brien , she knew that he had a daughter and gave him a pendant to give to Molly . ( ) Molly temporarily left the station with her mother for her safety . She returned shortly after . ( ) She attended a day care on the station . She went through the phase of not wanting to be near her father , and when Miles offered to drop her off at day care , Keiko said she was taking her to school with her so that Molly could experience a Vulcan program that taught basic problem - solving skills . ( ) Molly went with her mother on a botany expedition that lasted several months . When she returned , Miles was eager to spend the two days he had with her , but Molly wasn ' t feeling well . Later , however , she said she felt " lots better . " The day after , Molly again left with Keiko for half a year more of the trip . Miles told her to take care of her mother for him . ( ) Some six months later Molly , along with her mother , returned to Deep Space 9 from Bajor where she ' d acquired a Bajoran doll named Lupi . Molly was the one to tell her father that Keiko was pregnant again , this time with her little brother . Miles was looking forward to spending a lot of time with Molly , and tried to teach her how to play darts . While Molly had a good aim , she grew bored with it and opted to color instead . When she drew a pony , Miles asked if it had a name , but Molly said she " didn ' t know . " ( ) Molly loved to color , and often did so after dinner . She was , however , in charge of putting her plate in the replicator . She attempted to show Miles one of her drawings , while he was dealing with the experience of heaving two decades of time in prison ' imprinted ' on his memory for a crime he hadn ' t committed , but he got irritated and lashed out at her . She began to cry , and when Miles tried to apologize , Molly was too upset to listen . However , she later forgave her father , and welcomed him home with a hug and a " Daddy ' s home ! " ( ) In 2373 , Keiko went on a five - day trip to Bajor . During this time , Miles was to care for her plants . However , in a combined effort with Julian , he managed to kill a species of plant . Molly left her room and saw the dead plants , and warned her father that he would be in trouble . When Miles suggested that Molly be the one to break the news to her mother , she responded , " Not me ! " After Keiko returned , she threw Miles a surprise birthday party . Molly was present , and wore her new purple shoes just for her father . She also contacted her father at work to say hello . ( ) In 2374 , while on a picnic with her parents on a nearby planet , the eight year old Molly fell through an energy vortex . When the crew arrived to help , it was determined that she fell through a time portal 300 years into the past when the planet was uninhabited . When Chief O ' Brien reactivated the portal , the calculations were off by ten years , and an eighteen - year - old version of Molly appeared . Without Human contact for ten years , she had become feral and had a difficult time adjusting to life on Deep Space 9 . Molly was homesick for her planet , and the O ' Briens tried to recreate the environment that Molly was used to in a converted cargo bay . At first she made progress , but later became unmanageable . Starfleet wanted to commit her to a special facility . The O ' Briens decided to return her to the planet and send her back through the portal knowing that they would never see her again . However , when Molly went back , a flaw in the O ' Briens ' programming of the portal meant that she arrived in the past at the same time as her eight - year - old self , subsequently sending her past self back through the portal to be reunited with her family . ( ) Molly ' s younger brother , Kirayoshi , was born in 2373 , and was carried by Kira Nerys after a shuttle accident . During this time , Molly sometimes referred to Kira as her aunt . ( ) Before the Dominion takeover of Deep Space 9 and the start of the Dominion War , Keiko took Molly and Yoshi to Earth for their safety . ( ) Both Molly and Kirayoshi moved back to Earth with their parents in late 2375 , when Miles accepted a position as Professor of Engineering at Starfleet Academy . Initially , Molly wondered if they were not going back to Earth , because Miles had not informed Julian Bashir , his best friend . However , she was told that they were indeed going . Molly also showed interest in her father ' s model of the Alamo . When Miles warned her not to touch it , she retorted that she let him play with " her " toys . ( ) Appendices . Background information . Molly O ' Brien was portrayed by Hana Hatae ; the adult version of Molly was played by Michelle Krusiec , while the infant Molly was played by the Tadeski twins . This was done as lookalikes are often used to lengthen or ensure the best filming availability for both infants and animals onscreen . Hatae was born in 1988 , but the birth of Molly and her reappearances as a baby were filmed in 1991 and 1992 . Molly ' s first name was a tribute to two people : former " Star Trek " production staffer Molly Rennie , and Molly Berman , the daughter of executive producer Rick Berman . ( ; ) Molly O ' Brien was mainly seen on screen as a baby during the fifth season of TNG but inexplicably was old enough to talk when re - cast with Hana Hatae during the sixth season . Later that year , Benjamin Sisko stated that she was three years old . ( ) By the second season of DS9 – which aired simultaneously with the seventh season of TNG – her age was explicitly stated to be four and , towards the end of the season , five . ( ) By the sixth season of DS9 , Kira Nerys says she is eight years old . ( ) . Molly ' s age appears to be an example of a continuity error known as " " . Apocrypha . The of and established Molly ' s full name as Molly Miyaki Worf O ' Brien . Molly and Keiko play a part in the of , with Keiko briefly losing track of Molly during the Cardassian attack on the station until she is found by Odo , Keiko warmly thanking Odo for his help despite Odo ' s discomfort .