World's oldest semen still viable 50 years after it was first stored

Fifty year old ram sperm has been thawed and used to successfully impregnate 34 sheep in Australia, scientists reveal. They believe it is the oldest sperm ever to produce offspring and is the oldest viable stored semen of any species.
And some of the lambs born to the impregnated Merino ewes even had features that have since been bred out. The live birth rate matched that of sperm frozen for just 12 months. The semen has been stored at minus 196 degrees in liquid nitrogen in Sydney since being taken in 1968.
Associate Professor Simon de Graaf from the Sydney Institute of Agriculture and School of Life and Environmental Sciences at the University of Sydney said: "This demonstrates the clear viability of long-term frozen storage of semen.