The factors contributing to OATS can be broadly broken down into four categories – Genetic, lifestyle, testicular factors and testicular ejaculatory dysfunction. The genetic factors include defects in the sperm DNA, Y-chromosome defects and Klinefelter syndrome. Lifestyle factors that could contribute to OATS include high alcohol consumption, use of recreational drugs and smoking. Overheating the testes by taking many hot baths and showers, wearing tight briefs or overexerting yourself at the gym can also lower sperm count and motility. Drastic weight fluctuations, being overweight and being underweight can also contribute to OATS. Testicular factors that could contribute to OATS include testicular cancer, testicular trauma, chemotherapy, radiation therapy, ageing, enlargement of a varicocele and past infection of certain diseases such as mumps, malaria or syphilis. Testicular ejaculatory dysfunction refers to a set of conditions that obstruct the flow of semen through the male reproductive tract. This includes, erectile dysfunction, hypospadias, impotence, obstruction of the vas deferens, inflammation of the prostate or retrograde ejaculation, where semen is redirected to the bladder.