The following comes from a June 3 story on The Cut.

In the future, transfusions of aborted fetal stem cells might help those suffering from debilitating illness. But at the moment, it’s illegal for doctors to perform stem-cell therapy in the United States — though that doesn’t mean Americans aren’t already crossing the Mexican border to do it.

In a new documentary, The God Cells, director Eric Merola followed dozens of people who have conditions including Parkinson’s, multiple sclerosis, and muscular dystrophy as they sought intravenous fetal-stem-cell treatment in Tijuana. These people don’t want to wait around to see when, or if, there’s enough research for the government to approve the treatment.

Very broadly, a stem cell is a generalized cell that can become specialized as it matures. In embryos, stem cells divide and develop into different cell types, and in developed tissues they function as a repair system, replenishing and replacing worn out cells as they divide. (Fetal stem cells are considered superior to other types like embryonic, umbilical, and adult — more on that later.)

Because of these regenerative abilities, researchers have been looking into therapeutic uses of fetal stem cells for more than a decade, though under tight regulations and intense scrutiny. Before that, fetal tissue was used to create vaccines, including the ones for polio, rubella, chicken pox, and shingles. Even so, objections from pro-choice groups — and tepid research funding from the pharmaceutical industry that thrives off patented drugs — have prevented treatment from being widely available, despite the kind of stunning improvements documented in Merola’s film.

“I ended up going [to Mexico] about 12 times and honestly I was just kind of blown away,”  he said. “Most importantly, not everybody got better immediately or even later, but I saw enough to pique my interest.” A woman whose Parkinson’s resulted in severe hand tremors was able to play the piano again and a teen with cystic fibrosis improved his lung function enough that he could play basketball and play golf at altitude.

But not everyone fared as well, and Merola noticed that people who went for treatment sooner after diagnosis than later had better success. “I met countless Parkinson’s patients who’d had Parkinson’s for like 20 years and I stayed in touch with them and they didn’t really have any improvement. They had some things that got better, like maybe their eyesight, but it wasn’t what they were looking for….”