Three of the United States' brightest high school scientists, one boy and two girls, emerged as winners on Tuesday in the $1 million Intel Talent Search, among the top U.S. competitions for young innovators.

The 40 finalists faced a final competition in Washington before announcement of the winners at a black-tie dinner, according to the Society for Science and the Public, which runs the event.

The winners in three categories - basic research, global good and innovation - will each receive $150,000, it said in a statement. Second-place finishers will each get $75,000, and third-place prizes are $35,000.

Amol Punjabi, 17, of Marlborough, Massachusetts, won the basic research category for developing software that may help drug makers to create new cancer and heart disease therapies.

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Paige Brown, 17, of Bangor, Maine, studied water quality of six local streams high in E. Coli and phosphate contamination levels and led the global good category.

And 17-year-old Maya Varma of Cupertino, California, won the innovation category by creating a low-cost, smartphone-based tool to diagnose respiratory illnesses as accurately as expensive models used in medical laboratories.

Other finalists' projects include an encryption system with applications in cybersecurity, research on nanomedicine aimed at destroying blood clots that can cause heart attacks, and improved concrete seals for undersea oil wells, the society said.

The finalists are from 38 schools in 18 states. Two schools had two finalists apiece - Montgomery Blair High School in Silver Spring, Maryland, and the Massachusetts Academy of Math and Science in Worcester, Massachusetts.

Fifty-two percent of the finalists are female, a first in the program's 75-year history.

"This milestone is an inspiring sign of progress toward closing the gender gap in technology and engineering," said Rosalind Hudnell, president of the Intel Foundation. "We hope these finalists' outstanding work will inspire young people from all backgrounds to develop their interests in these fields."

Past participants have received some of the world's top science honors, including 12 Nobel Prizes, 11 National Medals of Science and 18 MacArthur Foundation Fellowships.

The competition is sponsored by semiconductor maker Intel Corp .