Stace Owens has no intention of leaving this world when he dies. He plans to stick around for decades or longer, preserved in plastic and displayed in a museum or medical school.

The 33-year-old real estate agent from Dallas is among more than 7,000 people who have agreed to donate their bodies for plastination, a process in which body fluids are replaced by liquid plastic. The plastic hardens, leaving tissues intact and allowing bodies to be displayed in their natural color and without formaldehyde.

The process was made popular by Gunther von Hagens' "Body Worlds," a controversial anatomy exhibit that puts real human specimens on show. Most are flayed and dissected, revealing their organs. Others are kept intact and displayed in dramatic action poses, such as a basketball player driving to the hoop or a runner in full stride.

"I've always been a big believer in science and medicine," said Owens. "It's like me kind of giving back to knowledge and to anyone out there who's interested in science."

But the show has been criticized by some as trivial, disrespectful and voyeuristic. Von Hagens, who developed the technique in 1977, insists he's helping viewers understand how their own bodies work.

"When I go to the people on the street, to the masses, they have to like what I show," the 62-year-old German anatomist said. "Therefore, they have to experience an aesthetic shock. Therefore, they have to open their hearts to themselves. Therefore, they have to fall in love with the specimen, and then it will keep in their minds."

More than 22 million people in 35 cities have visited the exhibit since it debuted in Japan in 1995. Since von Hagens' donation program began in 1983, 7,652 people have agreed to donate their bodies and 461 have already died, said Georgina Gomez, who manages the North American body donation program for von Hagens' Institute for Plastination. She's also a donor.

"I think for me personally that donating my body to science, and specifically to plastination, would be the one (method) that would provide the most good and the most benefit to future people," she said.

Owens, who has taken several anatomy and physiology courses, said he became interested in donating after hearing radio advertisements about the traveling show, now in Dallas and Phoenix.

"Seeing the exhibit just emphasized the fact that this was what I wanted to do," he said. "To me it was really a celebration of life. ... Continuing on with plastination is me helping with the educational process."

For other donors, plastination is a unique journey beyond death.

Susan Baxter, a 49-year-old homemaker from Fort Worth, said she decided to donate in part because she was against spending thousands of dollars on a funeral.

"My family can go to Tahiti for the price of a funeral," she said. "Why celebrate me in a box when they can go out and have fun?"

Baxter's decision was driven by other factors as well. About 30 years ago she was diagnosed with endometriosis, a condition in which tissue from the uterus lining grows outside the uterus, causing painful cysts. She said people might learn about the disease if her tissue were preserved and displayed.

"It's something that you want to do instead of being ashes or worm food, to be some kind of asset instead of being in the ground," she said.

When Owens and Baxter die, their bodies will be sent, at their own expense, to an embalming facility in Upland, Calif. From there, they will go to the Institute for Plastination, which has laboratories in Guben and Heidelberg, Germany, as well as in Dalian, China.

"We definitely request donors for input on how they would like to be plastinated," Gomez said, though the institute can't guarantee how or where the body will be displayed.

Gomez estimates about half of the donors are used in exhibitions and half are sent to medical facilities to be used in teaching. Some become full-body specimens, a process that takes up to a year to complete at a cost of between $40,000 and $60,000.

"Each specimen would be used in a way that would best represent their own human anatomy," she said. "Really it just depends on what's needed at that time."

Von Hagens and Gomez said the institute keeps track of donors, spread across 24 countries, with regular letters and meetings, as well as with donor cards, which are matched to death certificates when the donor dies. Some museums have created ethics panels before accepting the show to make sure all of the bodies were willfully donated.

But that hasn't stopped accusations that "Body Worlds" and similar shows have unethically accepted bodies.

German prosecutors said in 2004 there was no evidence that Von Hagens used the corpses of executed Chinese prisoners in his show, as some reports claimed. Von Hagens also denied the allegations.

More commonly, critics say von Hagens' shows violate the sanctity of death.

Carol Taylor, a health care ethicist who directs the Center for Clinical Bioethics at Georgetown University, said the exhibit is "purely for commercial amusement."

"My major objection stems from the belief that there's an innate dignity to humans that extends to our bodies," she said. "Anything that denigrates our bodies by commercializing them I'm opposed to."

Baxter and Owens, whose families support their decision to donate, disagree.

"The body is just a vessel," Owens said. "This is just what I have in this life."