Hyperspermia is an alteration in the ejaculate volume in the male. Specifically, a man has hyperspermia when his seminal volume at ejaculation is greater than 6 mL.
This is usually related to the size of the seminal vesicles since they are responsible for producing about 70% of the seminal quantity. However, the exact cause of hyperspermia is not known at this time.
Although hyperspermia can affect male fertility, it does not always occur. When the ejaculate volume is high, but the number of sperm in the semen sample is correct, hyperspermia should not be a problem in achieving a pregnancy.