In a new study published in Nature Communications, researchers from Massachusetts General Hospital (MGH) and their colleagues show that a single dose of an anti-Müllerian hormone (AMH) gene therapy is enough to induce long-term contraception in domestic female cats. Similar to previous successful work in rodents, the researchers created an adeno-associated viral (AAV) gene therapy vector with a slightly altered version of the feline AMH gene. They treated six female cats with the therapy at different doses, while three cats served as controls. While all the control cats produced kittens following two four-month-long mating trials in which male cat was brought into the female colony, none of the cats treated with the gene therapy became pregnant. "A single injection of the gene therapy vector causes the cat's muscles to produce AMH, which is normally only produced in the ovaries, and raises the overall level of AMH about 100 times higher than normal," senior author David Pépin from MGH writes in a statement. Since the AMH gene therapy does not impair sex steroids or affect estrous cycling and prevents breeding-induced ovulation, researchers say the method may be a safer and durable alternative to spaying female cats.