"I remember my, my first seeing her in the bassinet, and I'm 8 years old, and I see the dark hair – and even, for our babies, [it] was strange," Kathie says. Erin Moriarty reports on an incredible story of switched babies.
Even though Shirley looked nothing like her seven other siblings, there seemed to be a logical explanation. Their grandmother was French-Canadian and had had similar coloring.
Most of the family accepted that but Shirley's father, Jim Morgan, never believed that the child was his.
"In his heart, he knew it just did not fit that that was his daughter," Kathie says. But Jim kept his suspicions to himself. "He just decided they were given this gift of a baby, he's going to help mom raise her with the rest of us and make the best of it," Kathie says.
Forty years passed - and the Morgan kids had kids of their own.
Jim Morgan fell ill with a serious heart condition. At the age of 80, after he was told he had just weeks to live, Jim Morgan blurted out what he had feared for years: that Shirley wasn't his child.
Kathie was so determined to set the record straight that she scheduled DNA tests for her father, mother and Shirley.
The results took everyone by surprise: Jim Morgan is not Shirley's biological father. And Jean Morgan is not her mother.
"I never doubted," Jean says. "She was always my baby."
The news meant that the Morgans had come home from Campbell County Memorial Hospital with the wrong baby 43 years earlier.
For Shirley, the news was overwhelming, so much so that she didn't want to speak to 48 Hours about it.
Although Kathie loved her sister Shirley, for her, there was only one thing to do: "I've got a sister out there, and we're going to find her," she says.
First stop on Kathie's search was the hospital, where authorities gave Kathie official birth records from that night but the name of the other mother was blacked out. Through a librarian, Kathie heard about a way she might be able to read through those blackened out lines.
"We were desperate at this time," Kathie says. She soaked the paper in distilled water and Clorox for two days.
This uncovered the word "Polly." Armed with this, she went to the local library and began checking school yearbooks.
She found a picture of 17-year-old Polly Munoz in a 1958 high school yearbook. When she compared that picture with one of Shirley at roughly the same age, she knew she had a match.
But neither Kathie nor her mother had any legal right to see the other woman's birth records. Luckily, in about 20 states – including Wyoming – a confidential intermediary, like Ann Robinson, can see birth records and even sealed adoption files.
She found Polly's daughter, who was living in Phoenix. "I called her and told her that she and another child were switched at birth," Ann says. "There was dead silence on the phone when I told her."
For Kathie Morgan, the moment couldn't come soon enough. The chance to finally meet her sister, Debra – and for her parents to finally have their daughter back – was wonderful.
But for Debra Delay, the idea of meeting her new family was terrifying. Since first learning that she'd been switched at birth, Debra has questioned everything that's ever happened to her.
But there was little time to pull herself together. Debra's father was dying, so she left her home in Phoenix and headed to Wyoming.
"Mommy gave me a big hug and a kiss, and she says, 'We've been waiting for you for 43 years,'" Debra says.
"She come dashing in here, and wow, all heaven broke loose," says Jim.
Then Debra Delay met Shirley, who had taken her place in the Morgan family.
" I wish Debra had come home with us and Shirley with her rightful family," Kathie says. "I think the girls' lives would have made more sense."
Debra and her single Hispanic mother, Polly Munoz, started out in Worland, Wyoming, only about 100 miles away from the Morgans. Debra's mother later married and had two more children.
Debra grew up in a primarily Spanish-speaking neighborhood and, according to childhood friends, the tall, blonde woman always stuck out.
Debra loved her mother but says her childhood was miserable because she always felt like a misfit. "I knew all along that I wasn't with the right family," she says.
A cheerleader and homecoming queen in high school, Debra married soon after high school, but divorced without having children. She ended up in Phoenix 12 years ago.
It was the life Shirley was supposed to lead. Instead, Shirley grew up as the youngest girl of eight children in a large, tight-knit Irish clan.
Like the rest of the Morgan children, Shirley went to the local high school. She married young, had three children and later divorced.
Unlike Debra, Shirley never strayed far from her family in Gillette.
While she won't talk about it, Shirley is getting to know her biological mom, Polly. But her relationship with the Morgan family is now strained – and she's filed a lawsuit against the hospital for the emotional damage caused by this incredible mistake.