Deformed sperm cell. Coloured scanning electron micrograph (SEM) of an abnormal sperm cell showing a hockey stick" appearance due to residual cytoplasm. This is an immature characteristic in sperm cells, and makes them unable to fertilise 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: x6000 when printed 10cm wide."