TORONTO -- The average baby goes through thousands of diapers before it is toilet trained. That translates to tens of billions of diapers in North American landfills every year.

“My neighbour had a young baby and I saw how many diapers she was using,” Alexandra Miller told CTV News Toronto.

That’s why the North York teen pitched the idea of creating an “eco-friendly” diaper to her classmates when they entered ExploraVision, a STEM competition in which thousands of North American teens participate in every year.

At the time, Harriet Lerman, Miller’s classmate, says her mother was reading a book about mushrooms.

“And I knew that mushrooms were super good at carbon capturing, so I brought it up with my group members.”

“And then we found out how absorbent the roots were and then we decided to implement that and mix the two together,” said Alexandria Yau.

And thus, the concept for “Shiitake Diapers” was born. The girls proposed growing highly absorbent mycelium — the root-system of mushrooms — by harnessing harmful carbon dioxide. The mycelium would then be used as the basis of a bio-degradable diaper.

“Mushroom diapers — shiitake diapers, taking C02 out of the environment, using that to grow mycelium, and then to make a diaper that would reduce land waste, that is truly amazing, it’s so creative,” said their science teacher, Cindy Law.

It took a month of hard work for the grade 10 girls at William Lyon MacKenzie Collegiate Institute to develop the diaper.

“Like seven-hour zoom calls after class just to get our ideas organized or researched,” says Yau.

But the hard work came with a big payoff. The 15-year-old students won first prize in the ExploraVision contest that came with a $10,000 payout, for each of the teens.

“$10,000, I mean, that’s like a lot of money,” says Yau. “And I think I can really invest in my future.”

The award has extra meaning for these youngsters, given studies indicate women make up less than 30 per cent of the workforce in fields involving science, technology, engineering and math.

“I feel like the field definitely needs to be widened, especially for girls in STEM,” says Miller.

Of course, the grand prize usually involves an all-expenses paid trip to Washington, D.C., and a visit with Bill Nye, the Science Guy. Unfortunately, that all had to be cancelled due to the pandemic.

“I’ve been bummed out,” says Lerman. “I mean Bill Nye is honestly my idol.”

“I’m a little upset about it but I’m so glad that they decided to accommodate and make a virtual ceremony for us. I’m excited to attend that,” Miller added,