Background Inflammatory bowel diseases (IBD) typically affect young patients during the reproductive years, and reproductive issues are of key concern to them. Aim To evaluate the impact of IBD on fertility in both women and men with IBD who had no history of surgical treatment for IBD. Methods We searched MEDLINE, Cochrane Library, EMBASE and international conference abstracts and included all controlled observational studies that evaluated fertility in Crohn's disease (CD) and/or ulcerative colitis (UC) in women and/or men. Results Eleven studies matching our criteria were included. In women with CD, there was a 17–44% reduction in fertility as compared with controls. Reduction in fertility was linked to voluntary childlessness, while there was no evidence of physiological causes of infertility. Most studies did not find any reduction in fertility in women with UC as compared with controls. In men with CD, there was an 18–50% reduction in fertility as compared with controls with no difference in reproductive capacity. There was no evidence of reduced fertility in men with UC. Conclusions The infertility observed in both women and men with CD is due to voluntary childlessness as opposed to involuntary infertility. This voluntary childlessness is often based on incorrect beliefs about the impact of the disease on fertility and pregnancy outcomes. Our results reinforce the need to increase awareness among male and female patients that IBD does not itself lead to reduced fertility.