By Jamie Gangel and Elizabeth Stuart, CNN

(CNN) -- The Bush family might just be the only one in the United States where an inside joke includes some friendly ribbing about the possibility of becoming the leader of the free world.

George P. Bush, the oldest son of former Florida Gov. Jeb Bush, is the only Bush currently pursuing a life in politics. His own family teasingly calls him "47," a reference to the fact that President George H.W. Bush became known as "41" and President George W. Bush became known as "43."

For George P., as he's called by his family, and the rest of the younger Bush generation, it will be no easy task living up to their famous parents and grandparents. But their sense of duty and public service was instilled by both of their grandparents from an early age.

"One of Barbara Bush's favorite pieces of advice was, 'Don't worry if your children never listen to you. Worry more that they are watching you,'" said Jean Becker, former chief of staff to George H.W. Bush.

The 17 Bush grandchildren clearly have been watching, with many of them continuing the family's tradition of service, which goes back generations.

A favorite saying of George H.W. Bush was "any definition of a successful life must include serving others." The Bush dynasty already includes one senator, two governors, two first ladies, and of course, two presidents of the United States, but the family's future in politics remains unclear.

George P. Bush

In 2015, George P., 42, was sworn in as Texas land commissioner, a powerful job that includes managing Texas' land to bring revenue into the state. It's a massively important position in state, with the Texas General Land Office bringing in more money to fund public schools than the Texas lottery, and also managing the state's oil and gas revenues. It's also seen as a launching pad for higher office.

George P.'s life in the public eye began when he was just 12 years old. "I guess I was born to enter politics," he recently told CNN's special correspondent Jamie Gangel.

Motivated by his grandfather, George P. led the Pledge of Allegiance at the 1988 Republican National Convention. "[My grandfather] inspired me to think about public service and here I am in Texas, serving the good people of Texas," he said.

He also credits his grandmother, former first lady Barbara Bush, with encouraging him and his cousins to give back.

"It's not necessarily politics that is the only profession where you serve others," George said. "If you look at my generation, you'll see that we step forward and it's largely because of American heroes like my grandfather."

Jenna Bush Hager and Barbara Bush Coyne

Twins Jenna and Barbara, 37, are the children of former President George W. Bush and former first lady Laura Bush. The two have written several books together, including a new children's book about sisterhood.

While Jenna works as a TV host on NBC's "Today" show, Barbara found her path after taking a trip to Uganda with her father, during the height of the HIV/AIDS crisis.

There, she was struck by how many people lacked access to doctors and the medicine they needed. She has said that experience spurred her to co-found the Global Health Corps, a nonprofit organization aimed at creating a generation of leaders to transform global health systems.

Pierce Bush and Lauren Bush Lauren

Pierce Bush and Lauren Bush Lauren are two of Neil Bush's children. Pierce, 32, is the CEO of Big Brothers Big Sisters Lone Star, which has served more than 6,000 underprivileged children in Texas. He says the best advice his grandfather ever gave him was "get your jersey dirty."

"It's important to be thoughtful and to think, but doing something is far more important," he told Gangel. "He would always say, 'Did you get your jersey dirty?' which was, 'did you play in the game?' And I think, for him, life is about going out there and being a part of the competition but doing it for some purpose that's bigger than your own game."

Pierce says he also feels the impact left by his grandmother, who was known within the family as "The Enforcer." "I think my cousins and I are the people we are because of her discipline and her leadership," he said.

Lauren, 34, has chosen to tackle world hunger, as the CEO and co-founder of FEED projects. The company sells reusable bags that help purchase meals for children suffering from malnutrition in underdeveloped countries.

In December 2018, just days after her grandfather's passing, she made a public appearance at CNN's Heroes event in New York City, where she presented a Hero Award to a veteran and honored Bush Sr.'s service in the Navy during World War II.

The future

Some of the Bush grandchildren are in their early 20's and just starting their careers. There are already eight great-grandchildren, too.

Charles Walker Bush, 29, is the son of Marvin Bush and his wife, Margaret. He has followed his grandfather's lead of military service, as a Marine.

Lauren and Pierce's younger sister, Ashley Bush, 29, works in the film industry. She's the co-creator of a recent web series that featured the lives of women entrepreneurs.

"Their grandchildren are finding amazing ways to give back, in big ways and small," said Becker. "What this next generation is doing and accomplishing might just be George and Barbara Bush's greatest legacy."