Deformed sperm cell. Coloured scanning electron micrograph (SEM) of an abnormal sperm cell showing an exposed central core at the mid-piece at the base of its tail. This deformity can lead to the tail breaking off, rendering the cell immotile, meaning it will not be able to reach an egg cell (ovum). All men have a few deformed sperm in their ejaculate, but an overabundance of them can mean that the man is infertile. Magnification: x3500 at 6x7cm size.