Fertilised egg cells (zygotes): If there should be any supplementary egg cells left after an IVF/ICSI treatment, these can be deep-frozen and preserved in liquid nitrogen at - 196°C for a maximum of 5 years (Swiss law). For legal protection a contract has to be signed.
Sperm cells or testicular tissue:
During a fertility treatment there may arise various reasons to freeze sperm cells or surgically removed testicular tissue (so called TESE-sample).
Liquid nitrogen (- 196°C) is used.