Not all sperm survive the freezing and thawing process. Some cells may be damaged. If you have a serious illness, especially testicular cancer, you may already have lower sperm quality before freezing begins.
Or you may not have enough sperm to freeze. This affects roughly 11 out of 100 people with cancer who are referred for sperm banking.
There is usually a fee for collecting and testing a sample, plus yearly fees for storage. You may want to ask your clinic about these costs ahead of time.
For people who have not yet gone through puberty, an option called testicular tissue freezing is still being studied. Right now, it is only available through research programs at certain medical centers.