At a playground, I watched as a father lifted his two-year-old onto an elevated walkway. He and I were the only two fathers there, and I took it on myself to advise him. “You might not want to do that,” I said. “It’s a little high for him.”

“Oh, he’ll be OK,” said the other Dad. “He’s a tough little kid.” The child ran happily along the walkway, until he found a series of climbing bars going down and grabbed on one to climb.