One week before Christmas, Jeff Cronkhite gave his 2-year-old nephew, Dylan Rotert, the ultimate gift - a kidney.

"I'm honestly just in constant amazement that this happened," said Leslie Rotert, Dylan's mother. "Every day I just want someone to pinch me."

Since July, Dylan, of Marietta, had been living with severe renal failure and was put on dialysis. His parents, Leslie and Ken Rotert, were told by doctors to immediately begin trying to find friends or family members who would be willing to donate a kidney to Dylan, as a transplant was going to be vital to his health.

"The dialysis was just excruciating for him and for us," Leslie said. "He was put on peritoneal dialysis, so he essentially had a catheter put in the cavity below his diaphragm, with a tube hanging out of his body. The machine would shoot fluid into his body, let it dwell, then drain the fluid to take out everything that the kidneys would not."

Leslie said Dylan was able to sleep with the machine hooked up to him, but there were only three nights out of six months that his parents slept peacefully with no interruptions.

"It's a gravity pump, so if he moves or the tube gets close to his intestines or stomach wall, it would essentially suck on that too and it was extremely painful for him. It would do 12 cycles a night of filling, dwelling and draining, and an alarm goes off if the tube is clogged or twisted or is slow to fill or drain, so we were constantly by his side," Leslie said.

Cronkhite, 46, said he and his older brother, Mike, both of whom are Leslie's older brothers, were two of eight people who signed up to be tested for kidney donor candidacy. Vials of blood were pulled from them and sent to the lab, where it was determined that Jeff and Mike were the best candidates, almost completely identical on the scale of compatibility with Dylan's body.

"I just said I'm going to do it," said Cronkhite, a physicist in Silver Springs, Md., who received his doctorate from Georgia Institute of Technology. "We both were more than willing to do it, and I know he would have done the same, but I just knew that I would not have any fear. Leslie had been told stories about people who will get on the operating table and chicken out, and I just knew without any sort of hesitation that I would be able to do it."

But still, Leslie had her fears.

"She was worried at first, and one night we were talking on the phone and she just told me that if I was feeling nervous to let them know because they would need to start looking for another donor. But I had no doubt I could do it, and eventually she did too," Cronkhite said.

So on Dec. 18, Cronkhite laid on an operating table at Emory University Hospital as Dylan laid on another table across the street at Children's Healthcare of Atlanta at Egleston, waiting for the kidney that would save his life.

"I just had a great sense of clarity, and before we went into surgery they took my blood pressure and heart rate, just to be sure. You can be mentally OK with it and prepared, but I suppose you can't always control your physical reactions. But I told them I was ready, and my heart rate was at 56 and my blood pressure 122 over 75, so I really was," Cronkhite said.

Cronkhite said as soon as his left kidney was removed from his body, it was rushed to Dylan's bedside where doctors replaced his failed kidney with the new one.

Dylan left the hospital on Dec. 26, while Cronkhite was out after three days. But Cronkhite said the toddler has already seemed to surpass him in their recoveries.

"I've been in bed and he's running around, just as happy as can be," Cronkhite said with a laugh. "We've all just noticed that his energy level is so much higher, and his mental acuity has substantially improved. And to know that they're not having to do dialysis anymore, and to have that draining tube out of his abdomen that was just so painful to him at times, it was completely worth it."

"You would not believe that this kid was cut open from his sternum to his pubic bone just two weeks ago. He has been amazing," Leslie said.

Cronkhite now faces six weeks of recovery, while his immune system repairs the surgery's inflictions and thus causes daily fatigue.

"I'll wake up, a little later than usual, but not too bad, then I'll have a cup of coffee and think wow, I feel great. But two or three hours, it will just absolutely hit me and I'm out," Cronkhite said. "I've been told that some people will feel fine then go to work and crash, or have to pull over because they're falling asleep while driving, and I believe it. You really do think things are great, but that fatigue comes out of nowhere, and comes hard."

Cronkhite is staying at the Roterts' home as he recovers, and said even with the fatigue and somewhat lengthy recovery time, he would do it all again. He said he is keeping a journal so Dylan can read when he get older how Cronkhite felt about the boy and why he did it.

Leslie said her son is not quite out of the woods yet, as the next three to six months will show whether or not Dylan's body truly accepts the new organ. But the love and support of others has kept her constantly surprised, she said.

"We just moved here last November from DC to help with my mom before she passed in February, so when all of this happened over the summer, we honestly went an entire month with people bringing meals each day for us, either from Johnson Ferry Baptist Church or neighbors. And a lot of those people we didn't even know, they were just doing it out of kindness. That really meant so much," Leslie said.

Family friend Heather Moore said she raised almost $1,800 for charity when she and Cronkhite walked the American Kidney Fund Steps that Count fundraiser in October.

"Jeff is a very genuine guy, and from early on when he was tested, there was no question he had a genuine desire to help his nephew," Moore said. "He's just been so humble about it, and it honestly just never seemed to really phase him. He knew the pain his nephew and the family were going through, so there were no hesitations. He is my hero - he's literally given a part of himself to someone else."