The case will give hope to young men about to undergo treatment for cancer which may leave them infertile.
The boy's father had his sperm frozen when he was 17 before starting successful treatment for testicular cancer in the early 1980s.
"I'm 99 percent sure that it is the oldest frozen sperm sample used (for a live birth)," said Greg Horne, a senior embryologist at St Mary's Hospital in Manchester, England, which treated the baby's parents.
The man's sperm was stored in liquid nitrogen nearly two decades ago and was not thawed until he married and decided to start a family.
May 24, 2004
Baby born from sperm frozen 21 years ago
In what scientists are saying is a new record, a baby boy was born after being conceived with sperm frozen 21 years earlier: