Critics say questions about dangers that could arise with manmade organisms — which can reproduce on their own — remain unaddressed.

“The notion is that, as we engineer more complex systems, our ability to predict their behavior diminishes,” said Boston University microbiologist James Collins. “How can we ensure that we don’t create something dangerous? Now is the time to start thinking about it.”

Until manmade organisms are fully understood, Collins said, government security precautions required for handling dangerous pathogens might be appropriate.