There is now substantial evidence that coeliac sprue is associated with infertility both in men and women. In women it can also lead to delayed menarche, amenorrhoea, early menopause, recurrent abortions, and a reduced pregnancy rate. In men it can cause hypogonadism, immature secondary sex characteristics and reduce semen quality. The real mechanism by which coeliac sprue produces these changes is unclear, but factors such as malnutrition, iron, folate and zinc deficiencies have all been implicated. In addition in men gonadal dysfunction is believed to be due to reduced conversion of testosterone to dihydrotestosterone caused by low levels of 5 alpha-reductase in coeliac sprue. This leads to derangement of the hypothalamic-pituitary axis. Hyperprolactinaemia is seen in 25% of coeliac patients, which causes impotence and loss of libido. Gluten withdrawal and correction of deficient dietary elements can lead to a return of fertility both in men and women.