Objective: To determine the feasibility of achieving births using sperm retrieved from a solitary testis with cancer. Design: Prospective clinical study of azoospermicmenwith testis cancer in a solitary testis. Setting: Infertility patients in an academic environment. Patient(s): Azoospermic men with previous history of orchiectomy and testis cancer in a remaining solitary testis. Intervention(s): Viable sperm were retrieved by immediate microdissection of paratumor testicular tissue from orchiectomy specimen. Main Outcome Measure(s): Live births were achieved using sperm from immediate microdissection of orchiectomy specimen with testis cancer. Conclusion(s): Azoospermic men with cancer in a solitary testis have potential for fertility. Objective: To determine the feasibility of achieving births using sperm retrieved from a solitary testis with cancer. Design: Prospective clinical study of azoospermicmenwith testis cancer in a solitary testis. Settings: Infertility patients in an academic environment. Patient (s): Azoospermic men with previous history of orchiectomy and testis cancer in a remaining solitary testis. Intervention (s): Viable sperm were retrieved by immediate microdissection of paratumor testicular tissue from orchiectomy specimen. Main Outcome Measure (s): Live births were achieved using sperm from immediate microdissection of orchiectomy specimen with testis cancer. Conclusion (s): Azoospermic men with cancer in a solitary testis have potential for fertility.