PURPOSE: To evaluate the clinical phenotype and interpretability of TEX15 gene variants in a real-world cohort of patients with primary testicular disease. METHODS: We conducted a retrospective single-center study including patients with primary testicular dysfunction. Patients carrying isolated TEX15 gene variants (n = 7) were compared with a pathological control group (n = 145) from a cohort of infertile patients with primary testicular failure without identifiable genetic alterations. Clinical, hormonal, and seminal parameters were analyzed using non-parametric tests. Effect size was estimated using Cliff's delta. RESULTS: TEX15 gene variants were identified in 0.9% of the cohort. No pathogenic biallelic variants were identified. Compared to pathological controls, TEX15-positive patients showed lower FSH concentrations (p = 0.031), higher sperm concentration (p = 0.002), and higher total sperm count (p = 0.002). Azoospermia was absent among TEX15 cases but present in 62.1% of controls (p = 0.002). No significant differences were observed in LH, testosterone levels, estradiol concentrations, or testicular volume. Sensitivity analyses excluding biologically atypical subjects attenuated most observed differences. Overall, TEX15-positive patients showed heterogeneous clinical presentations with limited phenotypic specificity compared to other forms of primary testicular dysfunction. CONCLUSIONS: Our findings indicate that TEX15 gene variants, particularly in heterozygous state, have limited clinical interpretability and do not define a clearly distinguishable clinical phenotype. These findings suggest that isolated TEX15 variants, particularly in heterozygous state, should be interpreted cautiously in routine male infertility diagnostics pending further functional validation.