I'm wondering are gonadal stromel tumors only found in females?

No: Gonadal sex cord-stromal tumors are interesting neoplasms of the gonadal structures. The pathology of these tumors is reflected in Sertoli cell tumors, These lesions can occur in both male and female gonads. They are however more common in the testis where they usually exhibit a lobular pattern. In the ovary, tubular differentiation is usually the predominant finding. One variant of Sertoli cell tumor, the large cell calcifying form, appears to be restricted to the testis