Scientists have long sought ways to stop animal populations from growing too large, but current methods are often expensive or labor-intensive. Now a team of researchers from the California Institute of Technology has discovered a method that could render animals sterile with a single injection, according to a study published today in Current Biology.

In humans and all other mammals, gonadotropin-releasing hormone (GnRH) spurs the development of eggs and sperm. In this study, the researchers tested a shot that contains a small amount of DNA that enables muscle cells to produce special antibodies that attack GnRH. In the study, the researchers gave the shots to mice; two months later, after their bodies had started producing enough antibodies, the mice were completely infertile. And unlike similar methods that use the immune system to create these antibodies, this method could work for 10 years or more in animals without the need for booster shots, since muscle cells are some of the longest-lived in the body.