Bryan Johnson’s latest biohack is nuts.  Over the years, the tech mogul has turned his quest for eternal life into a public spectacle, subjecting himself to extreme anti-aging experiments and sharing how they affect even the most intimate parts of his body in startling detail . This week, the 48-year-old raised eyebrows by boasting about a new feat involving his testicles, which he said “may be a world-first breakthrough in fertility research.” “This should not be possible,” Johnson wrote in a May 7 post on X .  Biohacker Bryan Johnson, 48, claims to have pulled off a first-of-its-kind achievement with his testicles. Bloomberg via Getty Images The breakthrough? According to Johnson, he went from having 165 microplastic particles per milliliter in his semen to zero in just 18 months. “I am the first human ever to show a complete reduction to zero,” the millionaire biohacker wrote. He also shared the exact protocol he used to do it.…