Purpose: To investigate the impact of varicocele on pregnancy and live birth outcomes in men with clinical varicocele in controlled studies. Materials and Methods: A comprehensive literature search was conducted across the PubMed and Scopus databases using Boolean operators, covering all available records from each database's inception through June 30, 2024. The inclusion criteria focused on controlled studies that compared pregnancy-related outcomes—including pregnancy, miscarriage, and live birth rates—between men with clinical varicocele and those without. These studies included participants attempting conception either spontaneously or through assisted reproductive techniques. Results: Out of 3,532 articles screened, only two controlled studies met the inclusion criteria. The findings revealed no significant differences between men with and without varicocele in terms of time to achieve pregnancy (5.3 vs. 5.4 months, respectively; p=0.92) or the proportion of men who had previously conceived with their partner (58.9% vs. 63.4%, respectively; p=0.47). However, a significant difference was observed in live birth rates, with men with varicocele showing a lower rate than those without (71.2% vs. 76.4%; p=0.04). Conclusions: The relationship between varicocele and conception remains contentious, primarily due to the limited number of controlled studies available for analysis. Despite an extensive systematic search for controlled studies comparing pregnancy-related outcomes in men with and without clinical varicocele, only two studies met the inclusion criteria. These studies showed no significant differences in time to achieve pregnancy or previous conception rates between the two groups. However, men with varicocele exhibited a slightly lower, statistically significant, live birth rate compared to men without varicocele. This highlights the need for further research on this topic to provide evidence-based guidance on the impact of varicocele on fertility outcomes. © 2026 Korean Society for Sexual Medicine and Andrology. This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.