YAKIMA, Wash. -- Gaby Rodriguez would worry whenever anyone asked to touch her baby bump.

It wasn't because she felt shy or embarrassed. It was because the bulge -- fashioned from wire mesh and cotton quilt batting -- didn't actually contain a baby.

For the past 6� months -- the bulk of her senior year at Toppenish High School -- the 17-year-old A-student faked her own pregnancy.

Only a handful of people -- her mother, boyfriend and principal among them -- knew Gaby was pretending to be pregnant for her senior project, a culminating assignment required for graduation.

Her teachers and fellow students, except for her best friend, didn't realize they were part of a social experiment.

Neither did six of her seven siblings, including four older brothers, her boyfriend's parents, and his five younger brothers and sisters.

"At times, I just wanted to take it off and be done," she says. "I didn't want to go through this anymore."

But Gaby didn't give up the charade until Wednesday morning, when she revealed her secret during an emotional, all-school assembly.

The topic of her presentation: "Stereotypes, rumors and statistics."

"Teenagers tend to live in the shadows of these elements," she says.

Before taking off her fake baby belly in front of the entire student body, Gaby told her audience, "Many things were said about me. Many things traveled all the way back to me."

Then, she asked several students and teachers to read statements from 3x5 cards, quotes people actually said about her during the course of her experiment.

Her best friend, Saida Cortes, a 17-year-old senior who was sitting in the front row, read card No. 3: "Her attitude is changing, and it might be because of the baby or she was always this annoying and I never realized it."

It grew quiet in the gym as more and more quotes were read aloud. Then Gaby dropped her bomb: "I'm fighting against those stereotypes and rumors because the reality is I'm not pregnant."

She had been nervous about how the crowd might react. After all, she had been lying to them since October.

"It 'happened' at homecoming," says Principal Trevor Greene, making air quotes with his middle and index fingers at the word "happened."

"In essence, she gave up her senior year," he says. "She sacrificed her senior year to find out what it would be like to be a potential teen mom.

"I admire her courage. I admire her preparation. I give her mother a lot of credit for backing her up on this."

But, the principal continues, "I have a daughter that will be here next year, and I would not let her do it."

At first Gaby's mother wasn't sure what to make of the idea, either.

"I thought she was crazy," says 52-year-old Juana Rodriguez, adding it was difficult to lie to family members -- "It didn't feel good" -- but she felt she needed to support her daughter, who enlisted two mentors from Yakima Valley Memorial Hospital's Childbirth Education Program to help her with her project.

When Gaby approached Greene last spring, she says she worried he might say no. He says he was impressed with her determination. He also says he was "shocked."

"I heard her out," he says. "I listened to her presentation, her proposal. And then I went through all the difficulties I foresaw to making this happen."

People might talk about her behind her back. Her older brothers might want to beat up her boyfriend. And there might be backlash -- even broken relationships -- when students, teachers and family members learned the truth.

"None of that deterred her," Greene says, adding he felt he needed to get permission from the superintendent.

John Cerna signed off. In fact, he left the west side of the state -- where he had been attending a conference -- at 5:30 a.m. Wednesday in order to get to Gaby's 10:15 a.m. presentation.

"I wouldn't miss this," Cerna says, adding, "It's amazing that a young lady would take this challenge on. It was a well-kept secret."

Gaby began wearing her homemade, basketball-sized, prosthetic belly to school after spring break. Before that, she wore baggy sweaters and sweatshirts to conceal her faux pregnancy.

Her supposed due date was July 27, not quite two months after graduation.

Gaby and her boyfriend, 20-year-old Jorge Orozco, met at the homecoming game when she was a freshman and he was a senior. They started dating just over three years ago.

When Gaby told him her plan, "I thought she was nuts," the 2009 Toppenish High School graduate says. "I thought I was going to end up getting into problems with her brothers. I didn't really want to get into problems with anybody."

But "I was doing it for her," he says, adding, "My parents thought it was going to be a boy."

Gaby -- who has a grade-point average of 3.8 and serves as president of her school's MEChA, or Movimiento Estudiantil Chicano de Aztl�n, Club -- came up with the idea during her sophomore year Advanced Placement biology class with Shawn Myers. She's in his anatomy class this year.

"You saw the side comments and the looks at her stomach," says Myers, who says he wasn't disappointed -- "just concerned" -- when she told him she was pregnant.

He says he wondered: "How are we going to take all of the potential that's in this girl and make sure it manifests itself and not let this define who she is and let it be a roadblock to what she wants to accomplish?"

It's a question Hispanic teens are more likely to face than white teens, Gaby found in her research. Black and Hispanic teens continue to have higher pregnancy rates than white teens.

And most teens at Toppenish High School -- about 85 percent -- are Hispanic.

Gaby came clean to Myers and two other teachers, both women, Monday. The women, she says, seemed relieved.

Myers had a different reaction: "She kept talking, and it did not register. Then I just kind of leaned forward and said, 'Are you serious?' I told her, 'You've run a great value experiment. You couldn't tell anybody because you had to control the variables.'"

But, he says, "When you're running a social experiment, you're dealing with human emotions. The human person in me felt I had been lied to."

Wednesday, Gaby apologized to teachers and students for misleading them.

When she took off her baby belly, there were a few nervous giggles, and a loud, "Whaaaaat?!" from the audience.

Then, there was applause. And, at the end of the assembly, following a Q&A session, there was a standing ovation, the first one Greene says he remembers during his three-year tenure at Toppenish High School.

"She really fooled me. I never would've guessed it," says 17-year-old senior Vicente Villanueva. "I'm really surprised."

So was 19-year-old Angel Jalomo, a 2010 Davis High School graduate and Gaby's niece: "I didn't know what to say. I just started crying."

Gaby will present her research to a board of community members in May. It will include photos and video from Wednesday's assembly. And Gaby still needs to finish writing her report. But by revealing the project to students Wednesday, she can go on her English class trip to Ashland, Ore., on Friday without her baby belly.

Plus, she didn't want to be pregnant for prom. She already has her dress, a teal form-fitting mermaid gown with spaghetti straps.

Gaby plans to attend Columbia Basin College to study social work or sociology in the fall. And, she says, "I'm not planning to have a child until after I graduate."