Cancer drugs often work by destroying rapidly dividing cells, as these are a typical feature of cancer. Unfortunately, the drugs can also kill other rapidly dividing cells, including those that produce sperm. Some men choose to freeze sperm samples before therapy so they can use them for artificial insemination at a later date, but this is not an option for boys who have not yet reached puberty.
Kyle Orwig at the University of Pittsburgh School of Medicine in Pennsylvania may have a solution. He says that while boys don't make sperm cells, they do possess "spermatogonial" stem cells that will eventually produce them.
To see if these stem cells could be used to restore fertility, Orwig and his team took samples of the cells from the testes of prepubescent and adult male rhesus macaques, and froze them. The monkeys were then given chemotherapy agents known to shut down sperm production. A few months later, the researchers injected each monkey's own spermatogonial stem cells back into its testes.
Sperm production was re-established in nine of the 12 adult animals and started normally in three out of five prepubescent animals once they reached maturity. The resulting sperm were used to fertilise eggs and produce healthy embryos.