This man (not a doctor!) has invented a method to neutralize sperm in a way that would never have occurred to me. He uses the most basic principles of physics (magnetic charge) to neutralize sperm!
Realizing that sperm is negatively charging, he simply coats a short section of the inside of the vas (tiny tube going from testes to the penis, located in the scrotum) with a positively-charged polymer. As sperm travels in this coated tube, the ionic attraction causes damage on a cellular level in the sperm, the pull effect effectively destroying the sperm "tail" and preventing it from fertilizing a female but without hormonal/medical methods!
For me, as an engineer, this was a true revelation.