Jonathan Zimmerman teaches history at New York University and lives in suburban Philadelphia. He is the author of Small Wonder: The Little Red Schoolhouse in History and Memory (Yale University Press).

In 1907 Mark Twain published a scathing attack on Christian Science, which held that all illness lay in the mind. In his trademark satirical style, Twain congratulated the religion for providing “life-long immunity from imagination-manufactured disease.”

The other kinds of disease were real, Twain insisted, and their victims required medicine – not prayer – to get better. But Twain also condemned the growing movement to prosecute faith healers and parents for withholding medical care from children who died.

A century later, we know much more about what makes people sick and well. As Twain understood, though, we still need to balance the protection of children with the religious liberty of their parents. And that’s why we should retain narrowly crafted laws exempting parents from child-abuse charges if they resist medical care for religious reasons....