Walker Brown was born 11 years ago with "an impossibly rare and random genetic mutation—cardio-facio-cutaneous syndrome, a technical name for a mash of symptoms. He is globally delayed and can't speak, so I never know what's wrong. No one does."

"But there are other times too—moments of unstoppable happiness. Reading the paper next to a lake on a deck chair with Walker in my lap, laughing delightedly as I swear at the news. The four of us in bed together on a Saturday morning, Walker on his knees, towering for once over us all, and never happier. This is something, you see: Every time he is happy, he is as happy as he has ever been. Hayley, a delicate and skilled ballet dancer, twisting with Walker to music on the stereo, Walker on the moon with happiness. Twenty minutes from his life. Everyday occurrences for a normal child. But I know their true value."

It's a very long story. It took The Globe and Mail three weeks and 15 chapters to publish this story, but it's a journey worth undertaking.

"Walker was saved by medical technology. I am grateful, but under my gratitude lurks a terrifying question: What would have happened if nature had been left to take its course? We saved his life, but is it a life he finds worth living?

"...The biggest challenge, I find, is to be optimistic. Not about Walker — he takes care of that — but about his future. The longer I spend in the world of my son's disability, the more people I meet who rise to that challenge. They are some of the most impressive people I've ever encountered."