Daniel's cancer seemed to be slowing its inevitable advance late this spring when excruciating pain suddenly erupted throughout his body. He was rushed to the hospital and died that afternoon.

Hours later, family members finally convinced his wife Linda to let them take her home. Sitting at the kitchen table, numbly trying to comprehend her new reality, her cell phone rang. She answered automatically, listened for a minute or so, and hung up without responding.

"Who was it?" her daughter Kelly asked.

"They said it was the eye bank and wanted to know if we would donate your father's eyes." The two women broke down in sobs.

I didn't know what to make of the call then and I don't know what to make of it now. Granting a blind person the gift of sight is a compelling reason to make such a bold request. And getting a commitment post-haste is critical. But phoning a spouse just hours after she bid her husband a final good-bye seems—what? Insensitive? Cruel? Unconscionable?

Every year in this country, thousands of people go without organ transplants that, like a new heart or lungs, could add years to their lives, or, like new eyes, could enhance their everyday existences. And every year, thousands of people die who would be willing and even grateful to have their organs live on in others but who just never got around to taking the simple steps needed to ensure it would happen.

According to federal data, each day 75 people receive organ transplants in the U.S. However, an average of 20 people a day die awaiting transplants that can't take place because of the shortage of donated organs.

What a difference donated organs make. A Health Resources and Services Administration analysis of transplant patients found that in May 2009, 54.4 percent of lung recipients were still alive five years after their transplants. The numbers were even more impressive for other types of transplants: 69.3 percent of kidney recipients, 74.9 percent of heart recipients and 73.8 percent of liver recipients were still alive five years after their transplants.

States, activists and hospitals have waged intensive campaigns to increase the number of organ donations, and those efforts have paid off. Just this past Monday, Michigan reported that 35,265 people joined its organ donation registry in June, a 25 percent surge from the same month last year. That follows the start of a policy in April requiring employees in all Department of State offices to ask customers, time permitting, if they want to sign on to the registry. Many states have similar policies. And hospitals actively promote organ donation on their own websites and in outreach efforts.

But still the number of available organs is far smaller than the number that could—and ought to—be available. A few years ago I interviewed Freakonomics author Steven Levitt, who uses data mining to reach seemingly counter-intuitive conclusions about issues and trends. He suggested that asking people to sign up to donate their organs, no matter how easy we make it, is the wrong approach. Far more effective would be to assume everyone intends to donate their organs unless they sign a form specifying that they don't want to do so. In other words, have people opt out rather than opt in.

It's an intriguing idea. Tell me your thoughts about that, about organ donation groups calling grieving spouses and about any ideas you have for increasing the number of organ donations.