When medical journalist Rebecca Skloot began researching her book "The Immortal Life of Henrietta Lacks" -- about a woman whose cancer cells have been used in research to fight polio, cancer and AIDS -- she uncovered a tragic story that began with racism, poverty, ignorance and death, and ends with few satisfying conclusions.

In 1951, Lacks, a poor, black sharecropper and a mother of five, received free radium and radiation therapy for her cervical cancer -- the gold standard treatment of the day -- albeit in the "colored" ward of Johns Hopkins Hospital. There, a sliver of her tumor was excised and kept for study. The abnormally fast growth of her cancer led to her death, at 31. But it also proved invaluable to researchers worldwide.

What was so special about Lacks' cancer cells? "Scientists had been trying to keep human cells alive in culture for decades, but they all eventually died. Henrietta's were different," Skloot explains. "They reproduced an entire generation every 24 hours, and they never stopped."

Given this, their medical uses have ranged from in vitro fertilization to immunization. They've played a role in lifesaving breakthroughs, including the creation of the polio vaccine, which rid the paralyzing disease from a population it once terrorized. The cells have proved to be an inarguable asset to public health. But they were taken without permission.

In 1951, keeping public ward patients' biopsy samples was a common practice, regardless of their skin color, Skloot reports. No statute or code of ethics prohibited it. Even today, she says, using patients' discarded tissue or blood samples for research remains legal.

So Lacks' surgeon didn't violate the law when he took a tissue sample from her diseased cervix for study. But he did so without her consent, making the act a moral violation, Skloot says -- especially for Henrietta's survivors.

In what remains a largely unlitigated area of bioethics, Skloot has found a subject that's at once ripe for exploration and frustratingly inconclusive. Still, she poses a host of questions: among them, who should own the rights to excised tissue? What should researchers tell patients about use of their blood samples, long after they've left their bodies? And how can they guarantee their understanding of complex medical issues?

Specifically, the book focuses on Lacks' children. Largely uneducated, they never understood the nature of the experiments conducted with their mother's cells -- or, later, with blood samples taken from themselves by researchers seeking insight into Henrietta's DNA. So how could they give "informed consent"?

At the same time, they're savvy enough to feel cheated of a share of the profits enjoyed by those who created products derived from research using their mother's cells: "[T]hey made millions! It's not fair! She's the most important person in the world and her family living in poverty," one son says. "If our mother so important to science, why can't we get health insurance?"

It's a poignant question that wants an answer.

Susan Comninos is a writer in New York.