Microplastics Found in Every Human Testicle

What do the pyramids, the oceans, the blood of newborns, and human and canine testicles all have in common?

They've all been found to be host to cancer-causing microplastics — which may also, scientists hypothesize, be why sperm counts have been diminishing for decades.

A new paper published in the journal Toxological Science describes alarming results from a study that tested testicle samples from 23 humans and 47 pet dogs, finding microplastics in every single subject: 330 micrograms of microplastics per gram of tissue and 123 micrograms found in the dogs.

"At the beginning, I doubted whether microplastics could penetrate the reproductive system," paper coauthor Xiaozhong Yu told The Guardian. "When I first received the results for dogs I was surprised. I was even more surprised when I received the results for humans."

Besides the jarring prevalence, the team was also concerned about the heightened concentration of polyethylene and PVC found in the human samples, which came from postmortem subjects ranging in age from 16 to 88.

Though this isn't the first study to find microplastics in human testes and semen, the comparative concentrations between the human and canine samples is novel — and not in a good way.

Though the correlation isn't yet perfectly understood, some recent mice studies have found a link between reduced sperm counts and microplastics exposure, and the chemicals released by the pollutants may also be associated with some hormonal abnormalities and disruptions as well.

That's likely because PVC in particular is, well, super freakin' toxic.

"PVC can release a lot of chemicals that interfere with spermatogenesis," Yu explained, "and it contains chemicals that cause endocrine disruption."

More research is needed, but one thing's for sure: our degradation of the environment has come home to our own bodies, and we're only starting to understand how that will affect us all.

More on nuts: Scientists Grow Teeny Tiny Testicles in Laboratory