State fairgoers wait in long lines for purple shoulder bags and two-bit yardsticks. But will they donate their children's fingernail clippings or blood droplets for free ride tickets and a string backpack?

Genetic researchers at the University of Minnesota hope the answer is yes. During the first week of the fair, researchers will invite 500 children and their parents to answer health questions, agree to height, weight and blood pressure measurements and provide DNA samples.

The ultimate goal of the "Gopher Kids'' study is to map the genetic makeup of normal, healthy children -- and thereby identify the genetic defects that predict chronic diseases and health problems.

"If we know what's normal, then we know where to look for abnormality," said Logan Spector, lead researcher.

But step one is just testing out the fair as a recruiting site.

Spector said it can be challenging and expensive to find 500 average Minnesota children for research, but the State Fair presents a unique opportunity. The 1.7 million or so visitors each summer mean a wealth of accessible volunteers -- plus, the fair engenders a level of state pride that might encourage people to participate.

"They don't get any personal benefit," he said, "but they'll know they are contributing to science and that it's a project that's run by their university."

Then there are the little rewards: ride tickets and backpacks, as well as free passes to the State Fair for the next two years. A devout fairgoer since he moved from Georgia, Spector said he figured volunteers would need some form of enticement, and the U of M backpacks have been hot items at past fairs.

Of course, there's no such thing as a free Pronto Pup. The free passes are designed to bring the volunteers back in 2011 and 2012 for further questions and screenings.

In year one, the researchers will collect DNA samples only via saliva. Parents and children will also be asked to donate fingernail clippings and blood droplets, but they can decline.

"I don't think a lot of kids hope to go to the fair so they can get stuck on the finger [to give a blood sample], which is why we made this optional," Spector said.

The initial goal of the study is to recruit 500 volunteers and to assess whether they return for the second and third years. (Volunteers must include biological parents of children ages 1 to 11.) Gaining DNA from 500 volunteers wouldn't be enough for the researchers to identify the complex genetic sequences that predict good or bad health. But it would validate the State Fair as a recruiting site.

Spector said he would then seek a grant from the National Institutes of Health to recruit thousands more volunteers at the fair. DNA samples from them -- along with the original 500 volunteers -- might be enough to unlock significant genetic discoveries, he said.

Whether families volunteer remains to be seen. The concept of collecting DNA specimens for genetic research has been somewhat controversial in Minnesota. A privacy group, the Citizens' Council on Health Care, has repeatedly challenged the state's collection of newborns' blood samples, used to identify rare genetic and metabolic diseases.

The leader of the council, Twila Brase, gave credit to the Gopher Kids researchers for some of the privacy steps they have taken -- and for allowing parents and children (once they reach 18) to withdraw from the study at any time and order their genetic samples destroyed.

However, she questioned whether the State Fair is the right place for parents to make a serious decision about giving genetic information to research. "It's not a serious environment," she said.

Spector noted that many fairgoers already agree to cholesterol tests that require small finger-pricks for blood. The U has conducted other clinical studies at the fair in the past, he added, but not studies that take place over multiple years.

The website for the study assures that genetic information will be secured and viewed only by the researchers.

Even if the genetic information indicates people are at risk for disease -- or that participating parents aren't blood relatives to their children -- the results won't be shared with them.

Interested fairgoers can visit the U's building on Dan Patch Avenue or first visit the Gopher Kids website.

The DNA saliva test works best when people haven't eaten for 30 minutes -- a risky proposition at the State Fair -- but it takes place at the end of the screening. So volunteers can eat all the chocolate-covered bacon and cheese-on-a-stick they want beforehand.

Jeremy Olson • 612-673-7744