In 2009, researchers from the biotechnology company Oxitec released over 18,000 genetically modified mosquitoes in a bid to reduce the wild mosquito population. The mosquitoes were designed so that in theory, when these modified male mosquitoes mate with wild females, the offspring would be infertile. Release enough mosquitoes and you could crash the native population.

On Sunday, the researchers released the first results from the experiment. They estimate that the 18,000 released males made up about 16 percent of the total male population. When they examined mosquito larvae a few weeks later, they found that 9.6 percent of the mosquito larvae in the area carried the new genes. The takeaway: the modified males did in fact mate with wild females. The researchers estimate that a real reduction in the wild population would require a much bigger release, though: up to 12 times the release rate of the experiment.

The research was notable for another reason: despite the fact that researchers were releasing genetically modified organisms into the wild, the research was done largely in secret. The company first announced that the tests had been conducted nearly a year after the fact. Other researchers worry that this casual approach to disclosure could create a backlash against the technology.

For more on the controversy, see our November feature story, "The Wipeout Gene," as well as exclusive essays praising the technology and criticizing the release.