by Rebecca D. Williams

About the author: Rebecca D. Williams is a freelance writer in Oak Ridge, Tennessee.

“You’ll need a liver transplant,” Dr. Zeno says. She scribbles quickly on her prescription pad and dates it: April 17, 2025. “Take this to the hospital pharmacy and we’ll schedule the surgery for Friday morning.”

The patient sighs—he’s visibly relieved that his body will be rid of hepatitis forever.

“What kind of liver will it be"” he asks.

“Well, it’s from a pig,” Zeno replies. “But it will be genetically altered with your DNA. Your body won’t even know the difference.”

Obviously, this is science fiction. But according to some scientists, it could be a reality someday. An animal organ, probably...