Animal birth control could soon be just a shot away: A new injection makes male and female mice infertile by tricking their muscles into producing hormone-blocking antibodies. If the approach works in dogs and cats, researchers say, it could be used to neuter and spay pets and to control reproduction in feral animal populations. A similar approach could one day spur the development of long-term birth control options for humans.
“This looks incredibly promising,” says William Swanson, director of animal research at the Cincinnati Zoo and Botanical Garden in Ohio. “We’re all very excited about this approach; that it’s going to be the one that really works.”
For decades, the go-to methods for controlling animal reproduction have been spay or neuter surgeries. But the surgeries, which require animals to be anesthetized, can be expensive—one reason so many dogs and cats remain unfixed and feral animal populations continue to grow. Nearly 2.7 million dogs and cats were euthanized in U.S. shelters last year. A cheaper, faster method of sterilization is considered a holy grail for animal population control.
To get there, researchers have already created vaccines that trigger an immune response in animals. This response produces antibodies that block gonadotropin-releasing hormone (GnRH), required by all mammals to turn on the pathways that spur egg or sperm development. The vaccines in this class—including deer contraceptive GonaCon—have been shown to effectively work as both male and female birth control in animals. But, like many human immunizations, the vaccines rely on an immune response that eventually dwindles away, forcing the use of booster shots every few years.