So what causes Low Semen Volume? The need to increase semen volume is felt by millions of men across the world, as they suffer from a condition where their body is unable to produce sufficient seminal fluid. This condition is called low semen volume. In medicine, it is defined as a condition in which a less than normal amount of semen is produced in each ejaculation. Because there is an inadequate amount of fluid to bring the sperm in contact with the cervix, the low semen volume condition can cause fertility problems.