The doctors and nurses told Melvina Hernández that the decision was a matter of life or death for her and for her baby ready to be born: She needed an emergency Caesarean section. They also wanted her consent for one other procedure.

The 23-year-old mother-to-be was lying in the maternity ward of Los Angeles County-USC Medical Center four decades ago. She didn't speak English. She said she couldn't sign any papers because her husband wasn't there. The couple planned to have at least two or three children.

"If you don't sign, you'll die," the nurse said, waving a paper printed in English, as Hernández recalls in a new documentary. "Then the nurse grabbed my hand and signed my name."

The child was born healthy, and Hernández's life was changed in more ways than one:

"I didn't know I was sterilized until four years later."

"No Más Bebés" — "No More Babies" — tells the story of a nearly forgotten battle for reproductive rights that exposed numerous examples of women having their fallopian tubes tied allegedly against their will, or without proper consent, in the Los Angeles hospital in the late 1960s and early 1970s. The women tended to be poor Spanish-speaking immigrants from Mexico.

Director Renee Tajima-Peña is scheduled to talk about the film after a screening in the AFI Docs Film Series at the Landmark E Street Cinema on Monday at 7 p.m. (AFI is no longer accepting RSVPs to the event.) The film will be broadcast as part of the Independent Lens series on PBS stations starting Feb. 1.

In addition to the mothers, the characters in the documentary include hospital whistle-blower Bernard Rosenfeld, the doctor who smuggled out medical records that helped a young lawyer named Antonia Hernández and her colleagues launch a class-action lawsuit in 1975, Madrigal v. Quilligan. The case made novel use of the recently decided Roe v. Wade. Today Roe connotes abortion, but the Supreme Court's decision in Roe covered the range of a woman's reproductive choices. Relying in part on Roe, the lawyers in Los Angeles argued that their clients were being denied their constitutional right to have children.

Tajima-Peña and her co-producer, the historian Virginia Espino, dig deep into the history to show the complexities of the episode, which, in other hands, could have been reduced to a black-and-white morality tale.

Several former defendants have their say, including Edward J. Quilligan, the head of the women's hospital in the medical center, who says, "I don't know of anybody that was pushing family planning…on any particular group….I think any woman deserves a right to make a choice."

Another doctor, Jerry Neuman, says, "We busted our, ahem, in order to provide care for a lot of people — and got sued for it."

"I'm never interested in making films about villains and heroes," Tajima-Peña says in an interview. "I don't think that tells us anything. The point of the story was that things were very complex and you have people at all different levels of accountability."

This was a time when a book called "The Population Bomb" was a best-seller, and a supposedly looming "population explosion" was a trendy matter of concern. A presidential commission was formed to study the problem, and federal dollars poured into family planning programs at hospitals such as the one in Los Angeles. Things got out of hand in dozens of states, where coercive sterilization occurred, possibly the result of old racist, elitist biases reinforced by new worries about poverty and overpopulation. The victims tended to be poor white women and women of color. In the case of Los Angeles, added to the mix were language barriers and the pressures on an overwhelmed county maternity ward, where women labored in hallways, time was short and birth occurred practically on an assembly line.

"You have all these things going on, and that creates the possibility that a woman is going to go in and she's going to be sterilized against her will," Tajima-Peña says.

Who or what was to blame? That was for a federal judge to decide when the lawsuit came to trial in 1978.

It does not spoil the ending to say that the case helped lead to bilingual consent forms and bilingual counseling. Yet in those contested times, even the remedies were difficult to agree on. Some Chicana activists favored a waiting period before sterilization could take place, while some white feminists considered sterilization-on-demand to be a reproductive right.

What is undebatable is the emotional pain of the women who unwittingly lost the ability to have more children. They mourn for the lives that never came to be. Many mourned in secret: Their sterilization was a source of shame that they hid even from the children they had before the procedure. Some of those children, now adults, found out only when the filmmakers came to speak to their mothers.

In the film, one of the mothers, Consuelo Hermosillo, listens to an old recording made by the trial team, in which she described a recurring dream of bringing a newborn baby boy to Mexico. Friends and relatives want to see him, but she won't show them. He's a miracle, and she doesn't want anyone to see him.

Now, nearly 40 years later, the feeling of loss hasn't gone away.

"It's like when you bury somebody," Hermosillo says. "You're always going to carry it in your head."