This summer, Jeni Stepien walked down the aisle in Swissvale, Pa., arm-in-arm with the man whose life was saved 10 years ago by her murdered father's donated heart.

Though both bitter and sweet for assembled family members, the moment clearly demonstrated how deeply moving and important organ donation can be.

In fact, one person can save or improve the life of up to 50 other people by sharing his or her organs, eyes and tissue. But sadly, over 20 people die every day because of organ shortages.

Only 40 percent of U.S. adults are registered organ donors (48 percent offer their eyes; 45 percent tissue).

If you're one of the reluctant who worry that a doctor won't do everything possible to save your life because you are a donor, that's just not true.

Here's why: You're seen by the doctor who specializes in your condition, not the one who harvests organs.

Doctors have every incentive to save you. Not only do they care about you, but their reputation is on the line.

You also may worry that you'll be declared dead prematurely. In fact, organ donors have a right to extra tests to determine if they really are deceased, at no cost.

So if you've been on the fence about becoming a donor, think about what your legacy could do.

It's easier than ever to sign up. You don't have to wait until you renew your driver's license.

Apple's updated health app lets you register to become an organ, eye and tissue donor.