The contribution of environmental factors in infertility is not well quantified. However, it is well documented that smoking not only decreases fertility but also it increases the probability of acquiring other diseases such as cancer, heart and lung diseases. Fertility among light smokers (20 cigarettes / day) was 75% of that of nonsmokers and fertility among heavy smokers (more than 20 cigarettes / day) fell to 57% of that of nonsmokers