Men who are about to undergo medical treatment that will render them sterile (eg chemotherapy), or when they need treatments that will cause damage to sperm, can have sperm frozen before treatment is commenced. Some men may also wish to have sperm samples frozen before having a vasectomy.

Similarly, women about to undergo treatments such as chemotherapy that are known to damage eggs, can consider egg freezing. The most successful form of egg freezing involves a woman undergoing hormone injections for about two weeks, followed by egg collection as occurs in IVF.

Increasingly, single women are exploring egg freezing as a means of preserving their fertility. However, the process does not guarantee a successful pregnancy following thawing of the eggs and later use. Mark regularly consults women in this situation who are considering egg freezing, and he provides an honest and balanced opinion as to whether egg freezing is of value to the individual woman. In that way women can make an informed choice as to the return from egg freezing in their circumstance.