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assuming you mean a sperm and not a cingular cell of a sperm, it is about 1/18th the size of an ovum.
If both are healthy, both will be producing sperm.
Fish sperm is roughly 1/6 the size of the average human sperm. It also swims much faster and has fins.
You can become an sperm donor for contacting the sperm banks nearest to you; banks require that you are within 1 hour conmute from them.
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