SAN ANTONIO Civil rights activist Rosie Castro toted her painfully shy twin boys everywhere, and they weren't always thrilled about the outings: distributing political literature, attending farm worker rallies and visiting the voting booth.
But the early introduction into political life made its mark on Julian and Joaquin Castro, who left their hardscrabble San Antonio neighborhood to attend Stanford and Harvard Law School before returning to their native city.
Julian is now mayor of America's seventh-largest city, and Joaquin is a Texas state representative poised to win a seat in Congress. The brothers, 37, will be in the national spotlight Tuesday evening when Julian -- after an introduction by Joaquin -- delivers the keynote address at the Democratic National Convention in Charlotte, North Carolina, the first Latino to have that honor.
Julian Castro says he'll use the speech to highlight his family story as an example of the American Dream.
"Growing up, when we would get dragged to these events, I didn't want to be there," he said, recalling the outings led by his activist single mother. "Over time, as we got older, I developed a real appreciation of the importance of being involved in the democratic process."
The Castros' story is rooted in San Antonio's West Side, the predominately Mexican-American area where the brothers grew up, as did their mother and grandmother. The area also was home to former San Antonio Mayor Henry Cisneros, a once-rising Democratic Party star whose career derailed after he joined President Bill Clinton's Cabinet and was caught lying to the FBI about payments made to a former mistress.
Though it is within view of San Antonio's tourist-destination downtown, West Side residents generally earn less and are less likely to go to college than people in other parts of the city.
"The West Side is considered kind of a rough-and-tumble area to come from," said Henry Flores, a native who is a political science professor and graduate school dean at St. Mary's, a West Side university.
Still, Joaquin Castro said that he's "never met people with more spirit for life."
The Castro family's West Side roots trace back to 1920, when the brothers' grandmother, Victoria Castro, joined extended family members there as a 6-year-old orphan from northern Mexico. Their grandmother sometimes shared a bedroom with the twins and did domestic work.
Their mother, Rosie, went to college and got a master's degree. She now is a student affairs administrator at a community college.
Because of her, Joaquin Castro says, he and his brother "grew a civic conscience." Rosie said she sought to teach her boys that "you have to give back to your community."
Rosie also made a mark in politics. She ran unsuccessfully for City Council in 1971 as part of a slate of Chicano activists, stepping forward at a time when only Mexican Americans handpicked by the white political establishment had a chance of winning.
"That was the kind of environment her sons were exposed to, but they didn't buy that cultural nationalism stuff," said Flores. "Their generation crosses class lines, gender lines, racial lines a lot better."
Julian and Joaquin Castro were born in 1974 on September 16 -- Mexican Independence Day. The night before their birth, their grandmother won about $300 in a contest cooking menudo, a Mexican tripe stew, and spent her winnings to pay her daughter's hospital bill.
Rosie Castro and the twins' father, Jesse Guzman, never married and separated when the children were 8. Julian Castro said he has a good relationship with his father, a retired teacher, who plans to attend his Charlotte speech.
The Castro brothers rode the bus to public schools because the family didn't have a car. They finished high school in three years.
To pay for Stanford, they relied on scholarships, grants and loans.
In the entrepreneurial, fast-paced San Francisco Bay Area, Julian Castro seriously pondered jumping into politics back home. He was impressed by San Antonio's community spirit, even in the face of poverty and other problems. People passing on the street looked one another in the eye, he said.
At Stanford, where they majored in political science, the brothers also launched their first campaigns and won student senate seats, tying for the highest number of votes.
At Harvard Law School, Julian raised money to run for San Antonio's City Council. In 2001, at 26, he became its youngest member ever. After an unsuccessful run for mayor in 2005, he re-emerged to win the job four years later and easily won re-election in 2011.
Joaquin Castro became a member of the Texas Legislature in 2003 and is favored to win a congressional seat in November in a heavily Democratic district.
The rise of the Castro brothers didn't surprise their Stanford thesis adviser, political scientist Luis Fraga.
"They have always been equally able and equally confident in a low-income neighborhood as in a corporate boardroom," said Fraga, now an associate vice provost at the University of Washington.
Like many grandchildren of Mexican immigrants, Julian Castro doesn't speak Spanish fluently, although he says his comprehension is good. He now thinks he probably should have taken Spanish instead of Japanese in middle school.
San Antonio's government is run by a city manager; the mayor is more of a political leader and policy developer. Julian Castro is pushing ambitious initiatives such as a tax increase to fund a pre-kindergarten program.
The move has rankled some of his critics, who see his work as shrouded in personal ambition.
Kevin Wolff, the lone Republican on the Bexar County Commissioners Court -- San Antonio is the county seat -- said that the mayor is "exceedingly intelligent" but highly partisan.
"I see a serious lack of leadership at the local level, like street drainage, safety and security, trash pickup," Wolff said. "All of his concentration seems to be, ‘How can I shine a better light on myself from a national perspective?'"
Julian Castro's political goals don't involve statewide office in Texas -- at least not immediately. The Lone Star State hasn't elected a Democrat to statewide office since 1994.
"Something has to change in this state before, not just me, but any Democrat can realistically think that he or she has a shot," the mayor said.
And for now, Joaquin Castro seems content to be the one introducing the mayor, a role he also played this summer at the Texas Democratic Party convention.
He told the audience how to tell the brothers apart: Look for a wedding ring. Joaquin is single; Julian is married with a 3-year-old daughter.
When Julian Castro delivers Tuesday's keynote speech in Charlotte, a role that also led to the meteoric rise of Barack Obama, he'll have come a long way from the quiet boy tagging along with his mother.
"I thought they were never going to talk to anybody," Rosie Castro said of her sons. But, she added, "they got over it."
(Additional reporting by Jim Forsyth; Editing by Marilyn W. Thompson and Paul Simao)