Well frozen Hitler sperm is off the possibilities of Merkle now.
"The first major breakthrough in that area came in 1949 when A.S. Parkes and two British scientists developed a method of using a syrupy substance known as glycerol to protect semen from injury during freezing. The process was further refined in 1953 by Dr. Jerome K. Sherman, an American pioneer in sperm freezing."
cryobank.com/learning-center/sperm-banking-101/sperm-banking-history/