Created for Her Bone Marrow, Marissa Ayala, Now 21, Has a Living Sister to Show for It

There are obviously many reasons to have a child.

But bringing a new human being into the world for the express purpose of creating bone marrow for someone else?

It was extremely controversial 20 years ago.

However, 21-year-old Marissa Ayala doesn't seem to mind being created for her bone marrow. Her older sister Anissa is alive and well because of it. The story inspired the book "My Sister's Keeper" by Jodi Picoult and a subsequent movie starring Cameron Diaz.

"Today" reports people were livid when Time magazine featured the sisters on the cover of a 1991 issue debating the ethics of "baby farming." The girls' parents, Abe and Mary Ayala, got hate mail. Even now, Marissa tells the news show, people still occasionally cluck about how -- and why -- she came to be.

"People are entitled to their own opinions, but I am so glad that I am in this family," she tells "Today." "I could not have asked for a better family, so I've never questioned it."

Twenty years ago, Abe and Mary Ayala were at the end of their ropes. Anissa was 16 when she developed leukemia. Nothing helped. Chemotheraphy proved ineffective. Her older brother Airon wasn't a compatible bone marrow donor. Neither were her parents. An unrelated matching donor was found, but backed out.

Anissa was dying. So her parents, in their 40s, decided to have another baby in the desperate hope the child could eventually save Anissa's life.

It was a long shot, "Today" reports. At best. At 42, Mary Ayala had only a 40 percent chance of having a successful pregnancy. Her husband had to get his vasectomy reversed. And there was only a 23 percent chance the new baby would be a compatible donor.

"Everything had to align perfectly," Anissa's doctor, Stephen Forman, tells "Today."

They did.

Mary was seven months pregnant when she learned her unborn baby would be a compatible donor. Marissa was only 14 months old when doctors at the Hope National Medical Center in Duarte, Calif., inserted an inch-long needle into her and fed the marrow into Anissa's veins.

"Today" reports Anissa is cancer free, thanks to her baby sister (now about to graduate from college).

Marissa, who Time magazine called a "biological resupply vehicle," tells "Today" you can't argue with results. The critics don't bother her.

"They don't know my family, and they probably don't put themselves in our shoes and ask themselves, 'Would I do this for my child?' " she tells "Today."

One of those early critics was the news show's own Dr. Nancy Snyderman, "Today's" resident medical correspondent.

"It crossed so many medical ethical lines," Snyderman says on the show. "I remember thinking early on, I was very critical of this as a doctor. Then I thought, 'Well, as a mother, would I do it?' And then I thought, 'Yes, I would.' "

Now, Snyderman calls it "a case where the planets aligned and everything that could have gone wrong didn't, and everything that could go right did. But it did turn medical ethicists upside down."

A lot of people ponder why they are on this planet and spend their lives looking for a purpose. Marissa knows why she's here. She was born to save her sister's life.

"Without her and her sickness, I would not be here," she tells "Today." "And without me being a perfect match for my sister, she would not be here as well."

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