A father of a 9-year-old donated his kidney to another dad he'd never met before. He said it was an easy decision.

• Steve Sanders of North Carolina had a rare genetic kidney disease.
• He shared his story on social media, hoping to find a living donor.

In July, Chris Perez's wife showed him a Facebook post. It was about a single dad of two kids who needed a life-saving kidney transplant. Perez didn't know the man, Steve Sanders, but he saw himself in another dad. He also thought of his 9-year-old son, Nolan, born with a congenital heart defect, whose life had been saved by modern medicine many times. Donating to Sanders could be a way to pay forward the benefits his family had received, he thought.

"I don't know him, but if it was me, I would desperately want someone to help," Perez told Insider. "It was really easy to make that choice to help somebody else and give him the opportunity to see his kids grow up."

Perez visited a website that Sanders had set up and submitted preliminary paperwork to be a living kidney donor. He went through months of testing, and in January he donated his kidney to Sanders, a total stranger.

The big ask, the big give

There are about 90,000 Americans waiting for a kidney transplant. Since people need only one kidney to live a healthy life, it's possible to get a kidney from a living donor. As Perez researched living donation, he felt comfortable knowing that donating a kidney was unlikely to affect his life long term.

When Sanders' lab work showed that his kidney function was steadily declining, his doctors advised him that searching for a living donor was his best option. Waiting for a deceased donor can take five years or more.

Deciding to share his story publicly wasn't easy for Sanders. He's not one for social media, especially when it comes to the most personal aspects of his life. Still, he pushed himself to discuss his life as a single parent and how a kidney donation could help him be the best possible father for his children, ages 10 and 8.

A unique first date

When Perez was approved as a donor, he still had never talked to Sanders. He asked the medical team to pass along his number and told Sanders to reach out when he was ready.

The next day the two hopped on a call planning to just introduce themselves and ended up talking for more than two hours. When they got together for lunch, the banter continued, and they soon went to Perez's house for the afternoon so their families could meet each other.

As the transplant date approached, Perez's son, Grant, 9, drew pictures of the operation room and even invented a Super Kidney board game. Perez texted the pictures to Sanders.

"It felt great to know that everybody in his family was in agreement with what he was doing," Sanders said.

On January 12, Perez went into surgery to have one of his kidneys removed. When it was placed inside Sanders, it started working immediately.

"I knew it was a success when I woke up," Sanders said. "I didn't realize how bad I felt until I didn't feel bad anymore."

Today, Sanders has a better quality of life and a longer life expectancy than he would have without the transplant. He and Perez share their story to encourage others to think about helping people. It doesn't have to be as dramatic as donating a kidney to a stranger, Perez said. Donating blood, plasma, or signing up to be an organ donor can all make a difference.