"Duoo Hopeful" offers men's boxer shorts that are scientifically proven to keep almost all the phone rays away from the testicles.
And while it's unproven that the electromagnetic fields from mobile phones are dangerous (the International Agency for Research on Cancer says they're "possibly carcinogenic"), these French inventors argue that there's no point risking it.
"We got the idea in school when we saw a study about how electromagnetic waves from smartphones are a danger for men's fertility rates," Antoine Serouille, one of the three inventors, told The Local.
"So we thought about creating a special pocket for a phone, but that just cut out the connectivity, so we switch to protective underwear instead.
"We wanted people to be connected and protected at all times."
The result: boxer shorts that reviewers say are extremely comfortable and scientists say are extremely good at keeping the waves away.
They block the waves thanks to interwoven silver wire in the material.
Serouille, who says he wears the boxer shorts every day, points to France's high rate of testicular cancer as a potential reason that French people have been showing an interest in the product. Over 2,000 pairs have been sold so far.
He added that he would be glad to potentially play a part in bringing the statistics down.
"Of course, low fertility rates aren't just down to the electrical waves, it's also things like pesticides and junk food," he told The Local.
"But if we can help protect the future of France, then we'd love to."
The brand offers a "precious" package, which for €45 a pair gives full protection, and a cheaper pair at €30 that gives only frontal protection.
And it appears the product, which is made in France, has a bright future on the underwear scene.
The young entrepreneurs have secured €300,000 in investment through crowd-funding and are producing another 11,000 pairs of the underwear.
In October last year, another young French inventor made headlines for coming up with underwear he claimed was the "cure" for builder's crack.