Today’s chatbots aren’t likely to help lone actors invent a deadly pathogen, experts say. But newer models, trained in biology, may need stronger safeguards.

The technology is far from the only existential risk our species faces. But weighing such cosmic fears can become a mind-bending exercise.

In a new report, the A.I. start-up added that it could not determine whether the research was legitimate or nefarious, leading the company to shut down the work.

Under a new partnership, the Defense Department would play a larger role in biodefense and pandemic preparedness. Democrats warned it could allow a Pentagon cash grab.