We report on the finding of paternity in 1 patient with metachronous bilateral testis germ cell tumor (BTGCT) and in another patient with a unilateral testicular germ cell tumor and contralateral carcinoma in situ (CIS). These cases demonstrate that patients with BTGCT or CIS in their solitary testicle are not necessarily infertile. Surveillance might be a therapeutic modality in patients with contralateral CIS and active spermatogenesis and the desire for paternity assumed that they are included in close follow-up protocols.