Tatiana Maslany plays numerous clones in “Orphan Black.”

“Orphan Black,” whose third season begins this week, is the only show on television where you’ll hear this line: “Enjoy your oophorectomy!” The science-fiction series, which airs in the United States on BBC America, is filmed in Ontario and set, oh, somewhere nearby, right about now, in a world where doctors surgically remove the eggs from women’s bodies, freeze them, defrost them, and implant them in the uteruses of other women, or, sometimes, of the same women; sometimes they remove whole ovaries. It depends. The thing is: there are a lot of women. The show’s lush with them. It’s shocking.

“Orphan Black” stars the prodigiously talented twenty-nine-year-old Tatiana Maslany as a small population of clones. Maslany is the best thing about “Orphan Black,” with the writing a close second. As revealed in the show’s first two seasons, the characters played by Maslany are the product, or maybe it’s better to call them the progeny, of Project LEDA, a series of experiments conducted in a laboratory in the United Kingdom in the nineteen-eighties by a pair of geneticists named Susan and Ethan Duncan. Their work was illegal, and rather remarkably far ahead of the real-world cloning of Dolly the sheep, in Edinburgh, in 1996. (Over the past several decades, human cloning has been condemned or banned by more than a dozen American states, by many countries, and by the United Nations.) The clones the Duncans created in their laboratory were implanted, as fertilized eggs, into surrogate mothers, and grew up while under secret surveillance by “monitors” employed by the Dyad Institute, a sort of rogue genetics outfit lately headed by an evil clone named Rachel (Maslany), who was raised by the Duncans before their lab was destroyed in a fire that melted the floppy disks containing the genome sequence necessary to make more clones. That said, there’s room to hope that there are more clones still out there, and that Maslany will be able to try out a few more accents, hair styles, wardrobes, and postures. Really, she is breathtaking. Partly, that has to do with her versatility. But it also has to do with scarcity. There are very few good roles for women on television, and Maslany plays nine of them.

The show’s main character is Sarah Manning (Maslany), who, unlike the rest of the clones, is “wild”: she was rescued from Project Leda as a baby and placed in the home of a foster mother who seems to have been trained by the I.R.A. or something; she knows a lot about bombs and hideouts. The series’ debut involves Sarah discovering that she’s a clone; a lot of the other clones already know that. Ever since, Sarah has been busy helping some of the needier and more screwed-up clones, including Cosima (Maslany), a graduate student who is dying, due to a genetic defect; Alison (Maslany), an alcoholic soccer mom; and the mostly insane but resilient Helena (Maslany), who’s not only Sarah’s clone but also her twin, and who was raised in an orphanage in Ukraine before she was kidnapped and treated like an animal while being trained to assassinate all the other clones. Meanwhile, Sarah has also been trying to protect her young daughter, Kira, from the Dyad Institute, and in her free time she has been researching the history of Project Leda, which takes her to a church in whose basement are stored the records of something called the Cold River Institute.

“I’d like to see the archives,” she tells the church docent.

“The Institute was active a lot longer than most people think,” the docent says.

Scanning the labels on the archival boxes, Sarah mutters to herself, “1910, 1920 …” Digging through one box, she pulls out a black-and-white photograph labelled, “Most Perfect Baby, 1908.” The Cold River Institute was founded by Progressive Era eugenicists; its real-world counterparts were, too. The Eugenics Record Office was founded in Cold Spring Harbor, New York, in 1910. C. C. Little founded Jackson Laboratory, in Bar Harbor, Maine, in 1929. He worked with mice. As I once wrote in a book called “The Mansion of Happiness,” a study of the history of life and death, a mouse gene was the first gene ever cloned; the mouse genome was the first genome decoded. In “The Eggs of Mammals,” the Harvard physiologist Gregory Pincus, who started out studying rats, offered a chronicle of the hunt for mammalian and human eggs: “Pfuger, 1863—cat; Schron, 1863—cat and rabbit; Koster, 1868—man; Slawinsky, 1873—man; Wagener, 1879—dog; Van Beneden, 1880—bat; Harz, 1883—mouse, guinea pig, cat; Lange, 1896—mouse; Coert, 1898—rabbit and cat; Amann, 1899—man; Palladino, 1894, 1898—man, bear, dog; Lane-Claypon, 1905, 1907—rabbit; Fellner, 1909—man.” Duncan and Duncan, 1985—woman?

The Human Genome Project began in 1990; the sequencing of the human genome was completed in 2003. Genetic research has lately progressed so far that, this year, a group of scientists and practitioners gathered in Napa, California, to urge a ban on modifying the genetic material of human sperm, eggs, and embryos, a process known as germline editing. I talked to Jennifer Doudna, a prominent genetic scientist at the University of California, Berkeley, who was the lead author of an article in Science, calling for the ban. She’s never watched “Orphan Black” and says human cloning wasn’t possible in 1985, and it’s not possible today, either. It’s not her field—her lab studies RNA—but she says that “nuclear transfers are just incredibly technically challenging and the resulting embryos don’t survive, and if they do they have defects that lead to early death.” The reason for the ban on germline editing (which, of course, is not cloning) is that it’s been done on monkeys and there are rumors that people have begun trying it on human embryos, even though its unintended consequences are entirely unknown. Responsible genetic scientists want those experiments to stop. “The impression sometimes created among the public is that scientists are working away in their labs and maybe they’re not always thinking about the implications of their work,” Doudna said. “But we are.”

Understandably, it bothers Doudna that, in science fiction, scientists are very often sinister. That’s not entirely true of “Orphan Black,” where there are big-hearted scientists and evil scientists, in roughly equal number. Still, what’s most startling about the show isn’t its interest in science; it’s its interest in women. “You began menstruation very young,” a Dyad doctor tells Sarah, who submits to a medical examination after Dyad captures her daughter. Sarah, alone among the clones, is fertile. “You are all barren by design,” Ethan Duncan explains to Cosima. The series, which takes as its subject a field of research that led to the development both of several forms of contraception and of infertility treatment, is obsessed with female reproductive organs. On television, women don’t usually play grownup human beings; they play slightly oversize children, helpless and pouty, driven by appetites they can’t possibly understand. At the show’s surfeit of interesting, adult females, the mind reels. That they are merely egg containers would seem boringly reductive, in a biology-is-destiny way, except that it’s such an interesting answer to science fiction’s big question: Who creates life? It could be said that “Orphan Black” is a feminist “Frankenstein,” if it weren’t true that “Frankenstein” was a feminist “Frankenstein.” (Mary Shelley, after all, was the daughter of Mary Wollstonecraft, who, in 1792, wrote “A Vindication of the Rights of Woman,” and died five years later, in agony, of an infection contracted while giving birth.)