The presidency is not like a restaurant or car dealership. Fathers don't pass the business on to their children. In all American history, only one president's son has gone on to the White House, and that was 175 years ago.

And so people are interested in Texas Gov. George W. Bush not just because of his strong start toward the Republican nomination but because he is the eldest son of a former president. The relationship raises all sorts of questions--critical ones and admiring ones--having to do with legacy, child-rearing, competitiveness, revenge, clan, the psyche, silver spoons and old boyism.

Such questions were on everyone's mind here today. With one day of campaigning under his belt in Iowa, candidate Bush came to the family's splendid summer place to celebrate his father's 75th birthday. After lunch on the patio--hot dogs and hamburgers--the father and the son met with reporters to talk a little about their relationship.

It began as a simple photo op, as they say in politics. More than 100 journalists clustered at the top of the long drive, which winds past the guest cottages, past the tennis court and the swimming pool, among the blooming shrubbery and weathered firs of the Bush family compound at Walker's Point.

Everything looked just as the nation remembers it: that familiar house, with its gray shingled siding and mullioned windows and stone chimney; the surf pounding the anfractuous New England coastline; the fresh-clipped lawn, where daily briefings once charted the early escalation of the Persian Gulf War.

Out of that familiar house and onto that familiar lawn came those familiar faces, angular George and matronly Barbara Bush, who somehow made public life look appealing enough that two sons have been willing to follow them into it. Then came George W. and his wife, Laura.

As the shutters snapped, father and son stood side by side. Dad is taller and his features are sharper. The son resembles him through the eyes and around the mouth, but has his mother's fuller face, not to mention her slicing wit.

The wit was the first thing that showed. As they strolled onto the lawn, Barbara Bush looked at the media throng and asked, "Where were you in '92?" That was the year her husband lost his race for reelection less than two years after winning a war. Moments later, her son turned to his skydiving father and said, "Happy birthday, Sky King!"

Then came the questions.

The former president said he doesn't give his son much advice. "He doesn't need advice from me. I'll be there to support him if he just needs help and needs someone to love him. But I'm not in the advice bash . . . uh, bish . . . uh. . . . " The famously fumble-tongued president was at it again.

"I'm the same guy!" he said, and everyone laughed. Then he continued. "Barbara is more inclined to give advice. Sometimes it's very good advice, actually. Sometimes."

The former president--himself the son of a U.S. senator--said he does not believe the Bush family is a political dynasty, though his sons are governors of Texas and Florida. "We never felt entitled to anything. To me, 'dynasty' kind of connotes . . . expectations of something coming your way."

He predicted that his son would endure the rough edges of a campaign better than he did. "I used to get a little uptight," he said. "I think George is mentally prepared for this because he was there with me in good times and bad."

He said he'll "stay out of the issue business" when it comes to his son's campaign. "I've had my chance," he explained.

But the most powerful insight into their relationship came not from the father, but from the son. A reporter tried, rather daintily, to ask how it felt for President Bush to see his son so popular, given his own poor showing the last time he ran.

The approach was so delicate that the senior Bush had trouble getting it. Barbara Bush translated: "What he means is, you were unpopular and [your son] is popular."

"You mean I was unpopular," Bush repeated, and he charitably agreed. "I was." Then he added, "I think--maybe I'm a little egotistical--I think the American people, at least from surveys I've seen, are rather pleasant about me, and certainly about Barbara. So I don't worry about it. I mean I got defeated, and went home and stayed out of criticizing President Clinton. . . . He was elected and I wasn't."

He spoke a bit more and looked for another question. But his son broke in: "Let me say something about that." And then he spoke of some things his father has taught him.

"I learned that life doesn't end if you lose a campaign. I've learned that the most important things in life are much bigger than winning and losing a political race. That's why I feel comfortable about what I'm getting into. I've seen a really good man win, and I've seen a really good man come in second place. But he never lost his perspective and his values.

"He's a great dad. And that's the most important thing to a son. And so I come into this race liberated in a sense that if things work out--and I'm gonna fight like mad to see that they do--I believe I know what to do. And if they don't work out, I'll still have a great life. I'll have a mother and wife that love me. . . . And my dad has served as a great example for all of us who are lucky enough to be called his son and daughter. . . .

"This is an appropriate place to talk about it," said the candidate, meaning Walker's Point. In the distance, his brother Neil lounged on the grass beside one of the 10 grandchildren who had come for Poppy's birthday, which was Saturday. They had interrupted a game of catch to watch the scene. "This is a place where we find love and comfort, where we know the values of life that are bigger than straw polls and caucuses and primaries."

CAPTION: Barbara Bush rests a hand on son George W. Bush's face as his wife, Laura, left, and former president George Bush look on with smiles.

CAPTION: The elder George Bush steers boat carrying son and Secret Service agent.