What causes watery semen, and does it affect fertility? Reviewed by Jamie Eske and Alana Biggers, MD, MPH Semen is typically a thick, white fluid, but it can vary in color and consistency. Watery semen can occur due to low sperm count, lifestyle factors, and nutritional deficiencies. In this article, we explore some of the possible causes of watery or clear semen. We also discuss whether watery semen can affect fertility, the meaning of discolored semen, when to see a doctor, and treatment. Low sperm count Having a low sperm count does not automatically mean that a person is infertile. The World Health Organization (WHO) define low sperm count, or oligospermia, as producing fewer than 15 million sperm per milliliter of semen. Having a low sperm count can make it more difficult for a person to conceive but does not necessarily mean that a person is infertile. There is not always an obvious cause for having a low sperm count. However, some genetic conditions, ...