"The U.S. direct-to-consumer marketplace for stem cell interventions has been out of control, with hundreds of so-called clinics proliferating across the country," he said.Washington Post
What does "for stem cell interventions" mean here?
I know the direct-to-consumer marketplace, but I am not sure what is "stem cell interventions" here.
When I looked for intervention, longman said:
the act of becoming involved in an argument, fight, or other difficult situation in order to change what happens Longman
But still I do not get it, especially "for". What does it mean?