Restricting the ability to bring in the best foreign talent will hinder companies’ growth and in turn the US economy, the head of US biotech company, Flagship Pioneering, said at Semafor World Economy in Washington, DC.

People who immigrated to the US did so because it is the best place to realize their dreams — and because US laws adapted to allow for that, Noubar Afeyan, an Armenian entrepreneur and naturalized US citizen who cofounded Moderna, said on Thursday. “If we mess with that, we lose our regenerative capacity.”

Flagship, a Cambridge-based company, attracts a diverse global pool of scientists, engineers, doctors.

“There is a general notion that somehow immigration is not good for the future of this country,” Afeyan said. “There is nobody here who’s not an immigrant, and so when you realize that — you realize that what we have become 250 years later is entirely the product of immigration.”

IBM Vice Chairman Gary Cohn also said at Semafor World Economy that the tech company is “highly dependent” on foreign workers, and is an “active user” of the H-1B visa program, which the Trump administration has sought to overhaul.

Cohn cautioned against the use of the program to bring in “quasi unskilled labor,” but said that using H-1B visas “for someone who can create GDP, create economic growth, create prosperity for our country — I think that’s a phenomenally good use.”