The researchers were initially trying to isolate genetic causes of deafness, but instead found two different DNA mutations in the CATSPER 1 gene that effected a man's ability to produce a protein related to sperm "hyperactivity," or sperms ability to move fast enough to penetrate a female egg.
It is possible that antibodies could be developed that could bind to the defective protein thus creating healthy, active sperm. Additionally, the mutation would be selectively applied in pill form and create a male birth control pill. Both applications need more research and development. Nevertheless - there's hope for those who and don't want children.
Originally reported by the BBC.