Who decides whether your sick child lives or dies? You or the hospital? On Monday, the parents of 22-month-old Alfie Evans, who has extensive brain damage, were told their son’s life would be terminated by hospital staff. That night, the hospital turned off his ventilator. The hospital decreed “once all external signs of life have ceased,” doctors would confirm “that death has occurred.”

Alfie is now clinging to life.

Alfie’s parents tried appealing to British courts, but judges ruled on April 20 that “the hospital must be free to do what has been determined to be in Alfie’s best interests.” Determined by whom? Not his parents, who want to maintain life support. “He isn’t suffering, he isn’t in pain, he isn’t diagnosed,” his father explains. “It’s a straight-up execution.”

Alfie isn’t the first child sentenced to die by a British hospital. Last year, 11-month-old Charlie Gard died in a London hospital of a rare disease after the hospital refused to let Charlie’s parents transfer him to the United States for experimental treatment. More recently, a toddler named Isaiah Haastrup was taken off life support over the objections of his parents.

Can it happen in the United States? You bet. It depends on in what state you live.

Texas law gives life-and-death power to hospitals, never mind what families want. In most states, including New York, families are likely to win if they go to court to stop a hospital from pulling the plug. Unfortunately, they don’t know that and get steamrolled by hospital staff. Later, they may regret they didn’t hold out for more time with their child or a rare, unexpected improvement.

Pope Francis offered to take in Alfie at a facility in Rome that treats many brain-damaged children, and air ambulances stood by. The British hospital, backed up by the courts, opposed the transfer, even while denying him life support. The hospital is dooming him to die.

Sounds like what happens in Texas. In 2005, a court gave a Houston hospital the go-ahead to turn off the ventilator keeping baby Sun Hudson alive, over the mother’s objections. In 2017, again with a court’s okay, another Texas hospital cut off life support from 46-year-old Chris Dunn, who was awake and communicative, but descending into organ failure because of pancreatic cancer. His mother pleaded with the judges that the hospital was “trying to play God.” Texas law gives hospitals that power.

George Pickering’s adult son was on life support in a Texas hospital. Doctors declared him brain-dead, but Pickering felt his son squeeze his hand to communicate, and was convinced he could recover. When the hospital started to cut off life support, Pickering holed up in his son’s room with a handgun to stop the process.

“They were moving too fast,” he said. He was arrested and jailed, but when he got out, his son had recovered — a rare outcome.

In other states, laws favor parents who are willing (or able) to go to court. Jahi McNath, a teenager, was declared brain-dead by a California hospital ready to stop life support. Jahi’s mother won the right to take her daughter home, where she’s still living four years later on a ventilator.

Hospitals claim ending life support is in the child’s “best interest.” Don’t believe it. Oxford University ethics professor Julian Savulescu says there are few conditions painful enough to contemplate ending a child’s life. He cites Epidermolysis Bullosa, where a baby’s skin peels off relentlessly, causing extreme, unrelenting pain, infection and death within a year. But Charlie Gard, Alfie Evans, Jahi McNath and the other children denied care weren’t in pain.

Cost is why many hospitals pull the plug, says Mr. Savulescu. They should be honest about it. Instead, hospitals stick to their phony argument about protecting the child’s “best interests.”

They refuse to say more, hiding behind claims they’re protecting patient privacy. As if it’s okay to end a child’s life but not to publicly disclose the child’s condition.

Hospitals need to back off their authoritarian “we know best” posture. And show respect for parents.

Ms. McCaughey is a senior fellow at the London Center for Policy Research.