Scientists want to find a better way to freeze sperm without using harmful cryoprotectants. Current methods can damage sperm and reduce their movement after thawing. Slow freezing takes a long time and requires special equipment. Vitrification, a quick freezing method without cryoprotectants, is being explored as an alternative but has had limited success with mammalian sperm. The study discusses the challenges and benefits of vitrification compared to slow freezing, and the need for further research to improve sperm freezing techniques.