63 © The Author(s) 2016 A. Hamada et al., Varicocele and Male Infertility, SpringerBriefs in Reproductive Biology, DOI 10.1007/978-3-319-24936-0_8 Chapter 8 Effect of Varicocele Treatment Although multiple pathophysiological derangements have been documented in var- icocele, the central issue is whether or not repair of this condition improves fertility. Much debate has centered on this question, and rightfully so, as it is the bottom-line for both clinicians and patients. In this chapter, we examine the impact of varicocele treatment on male fertility parameters such as semen parameters, specialized sperm function tests and natural as well as assisted pregnancy rates. Impact on Semen Parameters Varicocelectomy studies report significant im in one or more semen parameters in approximately 65 % of the treated men [56]. In a recent meta-analysis, Agarwal et al. [179] combined 17 observational studies and randomized controlled trials us- ing sophisticated methods to minimize selection bias as described by the Potsdam Consultation [266]. Overall, sperm concentration, motility and morphology were increased by 9.7 million/mL, 10 and 3 %, respectively, after varicocelectomy. The mean amount of time for semen improvement and natural pregnancy after surgery was approximately 5 and 7 months, respectively [179, 267]. The reasons the why fertility potential is not always improved in varicocelecto- mized patients are still obscure, and robust data is lacking to determine prognostic factors that might help identify the best candidates for treatment. From the limited available data, it seems that infertile men undergoing surgery for large varicoceles are more likely to benefit from varicocelectomy [56, 267, 268]. As far as age is concerned, an interesting report suggested that advanced paternal age does not in- fluence the fertility outcomes of men with varicocele-associated infertility. It should be noted, however, that results might be biased by the fact that the group of men older than 40 years had a significantly higher proportion of subjects with secondary infertility as opposed to the other study with younger individuals [269].