LONDON — Charlie Gard, who turns 11 months old on Tuesday, was born with an extremely rare genetic disease. He is blind and deaf, and he cannot breathe or move on his own. He suffers from persistent epileptic seizures.

Now the British infant is at the center of a global debate, drawing in the Vatican and President Trump, over what medical treatment, if any, he is entitled to receive, and who decides — his family, his doctors or the courts.

“These terrible decisions have to be made all the time,” said Jonathan D. Moreno, a professor of ethics at the University of Pennsylvania. “It is very unusual for a case like this to explode on the global stage. They raise difficult moral and ethical questions.”

The London hospital that is treating Charlie has asked permission to remove him from life support. His parents want to take him to the United States, where they believe an experimental treatment has a chance — however remote — of prolonging his life, even though the disease has no cure.