Microplastics have been found on the top of Mount Everest, at the bottom of the ocean and now in human semen. Scientists discovered eight types of the tiny, cancer-causing plastics in all 36 men tested in the new study - including those used in Styrofoam and pipes. Semen samples found with particles used in piping had less mobile sperm, which the team suggested may link microplastics to the global decrease in fertility rates.