Punch Newspapers Sections Oladapo Ashiru Research shows that about 10 per cent of human infertility is caused by tubule obstruction, and this is usually, although not always, caused by infectious diseases transmitted sexually. One-third of African men are sterile because of epididymal obstruction caused by sexually transmitted diseases. For example, gonorrhea causes irreversible tubule blockage. This type of infertility caused by sexually transmitted diseases requires the most complex medical treatment, which includes new methods of assisted conception or reproductive technology. Obesity and Infertility WHO now recommends that persons that are overweight or obese should lose at least five per cent of their body weight using lifestyle changes such as dietary or health spa/detox clinics before attempting conception.