Betsy Hagopian was a repeater from Allentown, Pennsylvania who had been abducted since she was a teenager. She was among the women used by the Syndicate for hybridization experiments, having her ova harvested and stored to create the hybrid specimens. She was left barren and sick from the procedures, her body becoming full of tumors that did not respond to any treatment.
Betsy Hagopian was a founding member of the Allentown MUFON (Mutual UFO Network) group that met at her house. (TXF: "Nisei") The group's documents were stored in her basement and in her computer. (TXF: "Memento Mori")
By 1996, Hagopian went to the Center for Reproductive medicine in Pennsylvania for infertility treatment. Unbeknownst to her, her ova was extracted and kept at the Lombard Research Facility. (TXF: "Memento Mori") Hagopian became too sick to go home eventually and underwent treatment for her cancer. Dana Scully visited the hospital chamber with Penny Northern and Lottie Holloway, though they did not talk to her. (TXF: "Nisei")
At some point, Hagopian asked renegade hybrid Kurt Crawford to see to the MUFON files' safekeeping, fearing that all this information would soon start to disappear. Hagopian died in January 1997 and Crawford indeed executed her last will, but was killed in her basement doing so; the files were then stolen by the Syndicate's Grey-Haired Man. (TXF: "Memento Mori")
Betsy Hagopian is an important character in the X-Files mythology arc as many people and events revolve around her, but she is seen only briefly on screen undergoing a scan at an Allentown hospital.