Sperm morphology refers to the size and shape of the sperm. The amount of abnormal sperm is high in humans compared to other mammals, but most of the defects are subtle. Obvious flaws, such as 2 tails or 2 heads, account for only a small percentage of the defects. Most inadequate sperm appear as too small, or with kinks in the tail or abnormally shaped heads. We are satisfied if a semen sample has 14% sperm with perfect morphology. Individuals with overall low sperm count may not have enough normal sperm in the sample to achieve fertilization. Even though sperm morphology issues are almost impossible to correct, they can be overcome by using ICSI to insert the sperm into the egg.