Cynthia Robinson, trumpeter and founding member of Sly and the Family Stone

Girls don’t play trumpet, they told her.

Cynthia Robinson had an answer to that — one that would later resonate in the hit song she recorded with Sly and the Family Stone: “Thank You (Falettinme Be Mice Elf Again).”

More than any other lyric coined by the iconic hippie-funk band of the 1960s, that’s the one that most defined Robinson, said her daughter Laura Marie Cook, 51.

At a time when black women were relegated to roles as backup singers, Robinson blasted through barriers, sounding the signature trumpet that helped make the San Francisco band nationally famous.

Sly and the Family Stone, with its bracing trumpet flurries, was likewise unapologetically itself when it made its debut in 1967.

The band was difficult to categorize — a fusion of the groovy, earthy spirit of the Bay Area 1960s with gospel, R&B and funk. It was pioneering in terms of culture too: A mixed-race band that upset gender traditional roles, Sly and the Family Stone proved the perfect platform for Robinson, whose bold Afro, wild shouts and joyful dancing gilded its exuberant act.

Later, Robinson made sure her two daughters, a musician and a poet, followed her maxim. “She always wanted us to be ourselves,” Cook said.

Robinson died of cancer Nov. 23 in Carmichael, Calif. She was 71.

Robinson, born Jan. 12, 1944, in Sacramento, was the daughter of LaVern Robinson, a concert pianist, and William Robinson, a military man. Family lore held that the maternal line came from one of the first black families to settle in Sacramento, and the Robinsons were well-known in town, said Cook, also of Sacramento.

Cynthia began playing in the school band as a young girl. She tried various instruments. Then she heard someone playing the trumpet and knew she had to learn.

“She thought it was amazing,” Cook said.

“But Sacramento didn’t want to come along with the times,” she said. The trumpet was thought to be a man’s instrument, and Robinson was discouraged in school from taking it up.

She persevered. Cook said Robinson met Sylvester Stewart, whose stage name would be Sly Stone, while singing in a church choir with him as a young girl. Sometime later, he pulled up outside her house in a car full of fellow musicians.

Feeling protective, Robinson’s pianist mother came outside to demand who these young men were — and what were those instruments doing in their car? Could they play?

A long jam session followed. It turned out they could.

Robinson later followed up with Stone in San Francisco, where he was working as a disc jockey, and the two became a couple. In 1967, they became founding members of what would become a seven-member band.

Sly and the Family Stone hit it big with “Dance to the Music” in 1968, a top-10 single. Robinson’s shout exhorts listeners to “get on up and dance!” in the opening.

She didn’t think she could sing. But Stone urged her to. Her untamed shout became part of the band’s style. It was typical of Stone, who accepted neither racial, gender nor musical barriers.

“He was into group music. And if you were a good musician and could get along with the group, you could play,” Cook said.

Additional hits came with “Everyday People,” “I Want to Take You Higher” and “Thank You (Falettinme Be Mice Elf Again)”; the band was inducted into the Rock and Roll Hall of Fame in 1993. After it split in the mid-1970s, Robinson toured with Prince, played with former Sly bassist Larry Graham’s Grand Central Station and, until recently, toured as part of the Family Stone, which continues to perform.

Robinson’s daughters grew up in a home where “there was always music playing,” Cook said.

Robinson is survived by Cook and daughter Sylvyette Phunne Stewart — whose father is Sly Stone — and by five granddaughters, one grandson and six great-grandchildren.

jill.leovy@latimes.com

The Associated Press contributed to this report.