Texas Governor Greg Abbott yesterday signed a bill allowing clinics and companies in the state to offer people unproven stem cell interventions without the testing and approval required under federal law. Like the "right to try" laws that have sprung up in more than 30 states, the measure is meant to give desperately ill patients access to experimental treatments without oversight from the U.S. Food and Drug Administration (FDA).

In a state where unproven stem cell therapies are already offered widely with little legal backlash, bioethicists and patient advocates wonder whether the state's official blessing will maintain the status quo, tighten certain protections for patients, or simply embolden clinics already profiting from potentially risky therapies.

"You could make the argument that—if [the new law] was vigorously enforced—it's going to put some constraints in place," says Leigh Turner, a bioethicist at the University of Minnesota in Minneapolis, who last year co-authored a study documenting U.S. stem cell clinics marketing directly to consumers online, 71 of which were based in Texas.