In semen banks, semen is preserved at low temperature using which cryo protectant:-

Preservation of semen :- The most common cryoprotectant used for semen is glycerol (10% in culture medium). Cryoprotectant media may be supplemented with either egg yolk or soy lecithin Liquid Nitrogen is the medium in which these 'Cassettes' containing' sperms and cryoprotectants' are stored in. Cryopreservation of sperms,ova and embryos is one big step in the field of infeility. It avoids repeated aspiration . It also permits donation of eggs as well as of sperms to couples whose husband is azoospermic or wife is in capable of ovulation.