The most likely donors are victims of head trauma (from, say, a car or motorcycle accident), spontaneous bleeding in the head, or an aneurysm—patients who can be ruled dead based on brain-death criteria. But brain deaths are estimated to be just around 1% of the total. Everyone else dies from failure of the heart, circulation and breathing, which leads the organs to deteriorate quickly.

The current criteria on brain death were set by a Harvard Medical School committee in 1968, at a time when organ transplantation was making great strides. In 1981, the Uniform Determination of Death Act made brain death a legal form of death in all 50 states.

The exam for brain death is simple. A doctor splashes ice water in your ears (to look for shivering in the eyes), pokes your eyes with a cotton swab and checks for any gag reflex, among other rudimentary tests. It takes less time than a standard eye exam. Finally, in what’s called the apnea test, the ventilator is disconnected to see if you can breathe unassisted. If not, you are brain dead. (Some or all of the above tests are repeated hours later for confirmation.)

Here’s the weird part. If you fail the apnea test, your respirator is reconnected. You will begin to breathe again, your heart pumping blood, keeping the organs fresh. Doctors like to say that, at this point, the “person” has departed the body. You will now be called a BHC, or beating-heart cadaver.

Still, you will have more in common biologically with a living person than with a person whose heart has stopped. Your vital organs will function, you’ll maintain your body temperature, and your wounds will continue to heal. You can still get bedsores, have heart attacks and get fever from infections.

“I like my dead people cold, stiff, gray and not breathing,” says Dr. Michael A. DeVita of the University of Pittsburgh Medical Center. “The brain dead are warm, pink and breathing.”

You might also be emitting brainwaves. Most people are surprised to learn that many people who are declared brain dead are never actually tested for higher-brain activity. The 1968 Harvard committee recommended that doctors use electroencephalography (EEG) to make sure the patient has flat brain waves. Today’s tests concentrate on the stalk-like brain stem, in charge of basics such as breathing, sleeping and waking. The EEG would alert doctors if the cortex, the thinking part of your brain, is still active.

I saw something like this on Law & Order years ago, where a doctor prematurely declared someone brain dead because he needed to harvest some organ for some big donee.

I want to live as long as humanly possible. The thought that some doctor, whose incentives may not line up with my own, may prematurely declare me dead and harvest my organs petrifies me.

I also realize the insane selfishness of not just letting perfectly good organs rot away.

So I still go back-and-forth on this.

If organ markets were legalized, perhaps my incentives would change.