Figure 3. Forest plot presenting the effect of young and old father on digestive system abnormalities in their offspring: Three studies were included in the meta-analysis. The pooled OR in subgroup of young fathers and old fathers was 1.13(95%CI 0.98-1.30) and 0.90(95%CI 0.79-1.02), respectively. There was no heterogeneity in these two subgroups (I2=0.0%, 0.0%, respectively) amongst the studies.