OBJECTIVE: To assess the contribution of the male genome to the embryo's ability to develop and implant.DESIGN: Fertilization, embryo development, implantation and pregnancy outcomes were assessed in couples with a male partner suffering from spermatogenic failure and compared to normozoospermic couples.MATERIALS AND METHODS: ICSI cycles from Sept 1993 to Mar 2008 were reviewed and ejaculated and TESE cycles were identified. Only normal semen samples with a concentration of ≥20x106/ml, motility of ≥40%, and morphology ≥4% normal forms as well as NOA men undergoing TESE were included in the study. Female patients were then allocated according to the age groups as <35 or ≥35 yrs old. Fertilization, embryo cleavage and quality, and pregnancy outcome together with losses were compared.RESULTS: A total of 1652 ejaculated and 620 NOA patients were identified. When patients were categorized according to the maternal age and sperm source, women <35 yrs old inseminated with normozoospermic specimens (n=441) had a higher fertilization rate (79.1%) than the TESE (n=370) cycles (53.7%; P<0.001). The embryo quality and implantation rates were comparable between the two sperm sources (27.9 vs 30.6%). Furthermore, in spite of the similar number of embryos replaced, no differences were observed when clinical pregnancies (presence of a FHB) were compared (46.5 vs 44.6%). In addition, the incidence of pregnancy wastage for the ejaculate group was 4.9% (10/205) while for the NOA was 6.1% (10/165). When cycles with advanced maternal age (≥35 yrs old) were considered, the fertilization rate was similarly higher in the ejaculated cohort (76.7% vs 57.5; P<0.001) while, the embryo quality and the average number of conceptuses transferred were comparable between the two groups. Further, the clinical pregnancy rates were similar at 31.4% and 33.2% between the ejaculated and TESE sources. The proportion of embryos that implanted in the ejaculated group was 14.5% (536/3689) while in the TESE cohort, 17.2% (122/707). Interestingly, the rate of pregnancy losses was not higher in the TESE-treated patients (10.8%) than the normozoospermic group (15.5%).CONCLUSIONS: In contradiction to other studies implying that a suboptimal male gamete is responsible for poor embryo development and impaired implantation, we observed that men with compromised spermatogenesis reproduce similarly to their normozoospermic counterparts. From these findings, maternal age remains the sole culprit for the impaired clinical outcome. OBJECTIVE: To assess the contribution of the male genome to the embryo's ability to develop and implant. DESIGN: Fertilization, embryo development, implantation and pregnancy outcomes were assessed in couples with a male partner suffering from spermatogenic failure and compared to normozoospermic couples. MATERIALS AND METHODS: ICSI cycles from Sept 1993 to Mar 2008 were reviewed and ejaculated and TESE cycles were identified. Only normal semen samples with a concentration of ≥20x106/ml, motility of ≥40%, and morphology ≥4% normal forms as well as NOA men undergoing TESE were included in the study. Female patients were then allocated according to the age groups as <35 or ≥35 yrs old. Fertilization, embryo cleavage and quality, and pregnancy outcome together with losses were compared. RESULTS: A total of 1652 ejaculated and 620 NOA patients were identified. When patients were categorized according to the maternal age and sperm source, women <35 yrs old inseminated with normozoospermic specimens (n=441) had a higher fertilization rate (79.1%) than the TESE (n=370) cycles (53.7%; P<0.001). The embryo quality and implantation rates were comparable between the two sperm sources (27.9 vs 30.6%). Furthermore, in spite of the similar number of embryos replaced, no differences were observed when clinical pregnancies (presence of a FHB) were compared (46.5 vs 44.6%). In addition, the incidence of pregnancy wastage for the ejaculate group was 4.9% (10/205) while for the NOA was 6.1% (10/165). When cycles with advanced maternal age (≥35 yrs old) were considered, the fertilization rate was similarly higher in the ejaculated cohort (76.7% vs 57.5; P<0.001) while, the embryo quality and the average number of conceptuses transferred were comparable between the two groups. Further, the clinical pregnancy rates were similar at 31.4% and 33.2% between the ejaculated and TESE sources. The proportion of embryos that implanted in the ejaculated group was 14.5% (536/3689) while in the TESE cohort, 17.2% (122/707). Interestingly, the rate of pregnancy losses was not higher in the TESE-treated patients (10.8%) than the normozoospermic group (15.5%). CONCLUSIONS: In contradiction to other studies implying that a suboptimal male gamete is responsible for poor embryo development and impaired implantation, we observed that men with compromised spermatogenesis reproduce similarly to their normozoospermic counterparts. From these findings, maternal age remains the sole culprit for the impaired clinical outcome.