Bill Gates endorsed the use of a powerful and controversial new gene-editing tool to create malaria-resistant mosquitoes.

A handful of scientists have already created mosquitoes that are either infertile or resistant to the malaria parasite using CRISPR, a genetic cut-and-paste tool that allows researchers to precisely edit DNA. In several cases, researchers have also employed a related technology known as gene drives, which are designed to ensure the traits that scientists introduce are passed along to successive generations the majority of the time. That tool, which effectively identifies and snips out the naturally occurring form of DNA when it appears in offspring, promises to rapidly spread malaria-resistance through mosquito populations. And that’s what Gates said could offer a powerful weapon against the disease.

"Gene drives, I do think, over the next three to five years will be developed in a form that will be extremely beneficial," he said in the interview, ahead of speaking at the American Society for Microbiology conference in Boston. "Of course, that makes it a key tool to reduce malaria deaths."

Malaria, which is spread through the bites of female Anopheles mosquitoes, infects more than 200 million people each year and kills nearly 500,000, most of whom are children, according to the World Health Organization. That's why the Bill and Melinda Gates Foundation has poured resources into combating the disease for years, including a $150 million grant in 2014 to develop vaccines.

If gene drives work as expected, they could become one of the most effective tools against malaria, as well as other infectious diseases. But the raw power of the technology raises a new set of concerns as well. Any unexpected side effects on the species would also ripple through the populations and their ecosystems, a fact that could exacerbate already widespread public fears over genetically modified organisms.

Given the capabilities of CRISPR and gene drives, a growing number of policymakers and scientists have been pushing for limits on the use of these technologies and new approaches to this area of research. Some, notably including Kevin Esvelt at MIT, are also developing technological safeguards that could limit the spread of gene drives outside of the lab or within the wild. That includes so-called "daisy-chain" gene drives that fade away after several generations, a concept unveiled earlier this month.