Back in 2008 we reported that a child had been born with semen stored for 22 years. We thought we did well - but our record seems to have been well and truly broken.

We wrote then that Mike Kuzminski, a rock musician from Canada with Hodgkin‘s Lymphoma, banked his sperm and forgot about it till 22 years later when he wanted to start a family and learned he was infertile. In 2003 he tracked down the clinic and got the news from them “We totally have you here -- and you owe us $2,000 for storage." And on the 1st of November 2007 a baby boy was born.  The sperm they used had been frozen down in a Planer controlled rate freezer, and kept at liquid nitrogen temperatures.

But Andreas Szell and others report two live births from semen around 40 years old! In 1971, a man aged about 52, banked semen for frozen for long-term storage. In 2012 a patient using the donor sperm became pregnant after a second FET and had two healthy girls delivered. The authors conclusions are that low temperature storage in liquid nitrogen should maintain the viability of cells almost indefinitely because reactions that require molecular motion and/or activation do not occur at −196 °C. The adverse effects of background radiation during storage appear to be negligible since exposure of mouse embryos to the equivalent to 2,000 years of background radiation did not have a detectable effect on their viability.

For further information:  
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3696447/ 
http://planer.com/company/news/older-news-stories/146-child-born-with-parents-semen-stored-for-22-years.html