His growing fame has put his family under the spotlight as well, the subject of much curiosity, particularly among parents who want to know: How did the Andrakas raise not just one but two exceptional children?

Not by taking the well-worn and mocked "Tiger Mom" path of high-pressure parenthood, said Jane Andraka, 57, who works as an anesthetist at a hospital. "I do have a life of my own," she said.

Still, she and her husband Steve, 50, created a home environment where the boys were encouraged to find answers to their own questions, something that Jack says led him to use the scientific method from early on. Depending on their interests at the time, there might be a makeshift lab in the basement or E. coli in the kitchen.

There was a particularly memorable project that involved culturing bioluminescent bacteria in a bathroom, Jane Andraka recalled, and it grew so bright you could read a book by it. Until, that is, Jack's experiment involved introducing a toxin that led to what he calls "mass bacteria genocide."

The key to parenting, Jane Andraka has come to believe, is offering a range of opportunities but ultimately leaving the choice up to the kids themselves.

"You find what your child is interested in and allow them to find their own paths," she said. "We tried every instrument known to man. 'Here's a class …' Eventually, they find their own paths."

Helping two such inquisitive boys pursue their interests took a lot of time over the years, Steve Andraka said, but probably no more than parents whose kids are serious about, say, soccer or baseball.

Mark A. Runco, a psychologist who has studied exceptionally gifted children and their parents, said the family "ecosystem" is important.

"Giftedness like this doesn't happen without a family," said Runco, director of the Torrance Center for Creativity & Talent Development at the University of Georgia. "And in fact, the higher the level of exceptionality, the higher the level of commitment and investment is required."

Runco doesn't know the Andrakas, but, along with his mentor, the late Robert S. Albert, he has studied students who, like Luke and Jack, have attended programs at the Johns Hopkins Center for Talented Youth.

Parents have to walk a fine line, he said, between providing children opportunities to fulfill their potential, without putting undue pressure on those who likely are already motivated. It's what psychologists call the over-justification effect, he said, when external incentives decrease a person's own intrinsic desires.

From studying children who are exceptional in different fields, Runco said the unifying characteristic is what a colleague calls being "on fire" — the determination to pursue their passion. He wasn't surprised to hear, for example, that on his own, Jack reached out to 200 researchers at Johns Hopkins and the National Institutes of Health to find a lab where he could develop his idea for a diagnostic test.

"But he also has to have a mom driving him there, and tolerating this," Runco added.

And that is what Jane Andraka did, wearing out several Ford Escort station wagons ferrying Jack to math competitions and, ultimately, to the Hopkins lab of Dr. Anirban Maitra, the sole researcher to respond positively to his appeal for lab space. Jack would go there after school, sometimes working late into the night or even early morning as Jane waited, and sometimes slept, in the Escort.

In the lab of Maitra, a leading pancreatic cancer researcher who has since moved to the MD Anderson Cancer Center in Texas, Jack turned his idea into reality.

Jack had been researching pancreatic cancer since a family friend he considered an uncle died of it. One day during his freshman biology class, he was listening to the teacher talk about antibodies while surreptitiously reading a journal about carbon nanotubes, cylindrical molecules that have a diameter 1/50,000th of a human hair and carry intriguing electrical properties.

His idea ultimately took shape: He would take antibodies to a protein, mesothelin, which is found in the blood of persons who have pancreatic cancer, and apply it to nanotubes. He would spread the mixture on ordinary filter paper and drop a bit of a person's blood on it. Any mesothelin present would bind to the antibodies and force the nanotubes to spread farther apart, changing the electrical charge between them. The change could be measured — with an ohmmeter he bought at Home Depot for $50 — and reveal the presence of cancer.

Since winning the Intel grand prize for the test, Jack has gotten a patent for it and is working toward getting it produced, tested and on the market, a process that could take five to 10 years, he said.

In the meantime, he has already launched his next project, leading a team of other scientists his age in a $10 million competition, the Qualcomm Tricorder XPRIZE, to develop a handheld device to monitor and diagnose a user's health condition.

His travels continue, yet he has opted to continue his remaining 1 1/2 years of high school. He took the SAT this fall, and while he would rather not publicize his score, suffice it to say he did very, very well.