Few studies related to parity address the changes in anorectal function in women. Since the majority of patients with rectal prolapse are women, we undertook this study to assess the role of parity in the development of rectal prolapse. We retrospectively reviewed defecography studies performed on 354 female patients over a 10-year period. Studies noting the presence of intra-anal and external rectal prolapse (full thickness protrusion of the rectum into and through the anal sphincter) were reviewed. Cases with intrarectal or hidden rectal prolapse, a condition of lesser clinical importance, were excluded. The obstetric histories of the patients with rectal prolapse (n = 27) were compared to those of patients without rectal prolapse (n = 88). There was a larger proportion of nulliparous women in the rectal prolapse group than in the group without rectal prolapse, suggesting that factors in addition to parity play a role in the development of rectal prolapse. However, parous women with rectal prolapse had delivered significantly more children (3.3) than parous women without prolapse (2.5) (P = 0.03). The exact cause of rectal prolapse remains unclear. Childbearing appears to play a limited role in its pathogenesis since nulliparous women are also at risk of developing rectal prolapse.