A dog with cryptorchidism should never be bred. Neuter your male. Retained testes can turn cancerous with greater frequency.
Read the recommended pre-recs for breeding, and familiarize yourself further with the breed before you consider doing anything. What lines are the dogs? What is the pedigree? How have you proved your dog's abilities? (Sorry crawling under a fence on command isn't a tangible test for breeding worth) What are the hip/elbow scores? What do you know about the dam/sire? How did they produce? Grandparents? Greatgrandparents? The dogs may come from good bloodlines, but what have you done to prove the breeding dogs? Additional health tests - DM? Go deeper into the breed, and educate yourself further before considering breeding - it is the responsible thing to do...
Thinking About Becoming A Breeder? - German Shepherd Dog Forums
"Should I breed my dog?" Flowchart