When it comes to detecting new organisms that emerge from exotic places and cause global havoc, the US military is ready. The Pentagon operates infectious disease labs and surveillance networks in places like Kenya, Georgia, and Thailand, as well as a giant research center and vaccine-making unit just outside Washington, DC.

All that effort makes sense, with 200,000 US troops deployed at bases in 171 countries that can encounter a wide range of emerging biological threats. But Pentagon planners are starting to wonder what happens if the next deadly flu bug or hemorrhagic fever doesn't come from a mosquito-infested jungle or bat-crowded cave. With new gene editing tools like Crispr-Cas9, state enemies could, theoretically, create unique organisms by mixing-and-matching bits of genetic information.

As this scenario evolves from sci-fi to real-world possibility, many public health experts, biology researchers, and even the military have begun to examine possible threats, according to Christian Hassell, deputy assistant secretary of defense for chemical and biological defense. “We had people asking us, ‘How is the government responding to this? What is the threat that it poses, if any?’”

So Hassell and his colleagues at the Pentagon funded a year-long review by the National Academies of Sciences of the biodefense vulnerabilities created by synthetic biology. This week, the committee of experts held their fourth of six meetings in Washington, inviting academic scientists, biotech CEOs, and public health experts. A preliminary report outlining the scope and direction of the probe is undergoing “classified review” before being released to the public, and a final report—with recommendations—is due next year.

Those results could have implications for defensive strategies against a new type of bioweapon, potentially more difficult to identify because it resembles its “natural” counterpart. And that defense could start at home—by limiting biological research that has potentially nefarious applications. The final review will have the potential to guide regulations on federally-funded research labs.

Conflict over the need for future regulations spiked during the public portion of the meeting on Thursday—likely continuing on Friday behind closed doors. Some scientists at the meeting felt that the molecular biology community is already doing enough to monitor itself: The academic biology and DIY bio-hacking communities have voluntary codes of ethics to deter experimentation by would-be bad guys. And they fear what might happen to important genetic research if the Pentagon gets too paranoid.

They point to 2014, when the federal government halted 18 studies on so-called “gain of function” research that tinkered with viruses like MERS, SARS, and the flu to make them more likely to transmit in humans. The White House is taking another look at that moratorium to determine whether it still makes sense. Many scientists hope the ban is lifted—they argue understanding how viruses mutate is critical to stop them.

Scientists at the meeting expressed a range of ideas about how the military could best defend against biological threats. Sriram Kosuri runs a synthetic biology lab at UCLA that has developed libraries of DNA sequences that can be developed into new kinds of organisms. While he understands the possibility of a lab-engineered threat, he believes the Pentagon and federal health officials should focus on responding to emerging public health menaces rather than monitoring academic labs that use genetic manipulation tools. “There’s a legitimate threat of emerging viruses and we need to be prepared for those things,” Kosuri said during a break in the meeting. “The tiny threat of engineered viruses is miniscule compared to that.”

The Pentagon could also use the country's surveillance skills and genetic smarts to outwit biological bad guys. Howard Salis at Penn State has developed a computer program to predict what a new organism will do based on its genetic sequence. He thinks the best way to stop bad actors is at the beginning. “How do you stop someone from getting at the testing stage, or at the clinical stage of doing something bad?” Salis told the audience. “If you catch that actor trying to design the system, it's early in the process, it's easy to see what they are designing.”

For now, the threat of a hyper-lethal designer virus remains hypothetical. “This is not a tomorrow threat, it might be a tomorrow-tomorrow threat,” says Daniel Gerstein, an analyst at the Rand Corporation and former science policy advisor for the Obama administration. “I don’t think it's purely science fiction. But we have not seen a lot of terrorists looking to manipulate genome sequences.”

And even if they do, the good news (for now) is that responding to a super-charged human-made virus is pretty much the same as responding to a nasty Ebola- or Zika-like outbreak, according to Cmdr. Franca Jones, chief of global emerging infections surveillance for the Pentagon’s Defense Health Agency.

There are ways to determine whether a flu virus comes from a lab or the jungle. “We should be able to detect newly created organisms using a variety of methodology we have available, DNA sequencing being one,” says Jones. But whether it’s natural or lab-grown, public health officials will still need the resources to respond quickly to a infectious disease outbreak. “When it comes to our infrastructure to respond,” she says, “I don’t think there is much difference.”