Ejaculation

Blood in the semen
It is scary to notice blood in your semen (ejaculate). It is likely that you will immediately think that you have a serious disease, such as cancer. Not so; most of the causes of blood in the semen are not serious. There have been several scientific studies of this problem and they all came to more-or-less the same conclusion, which is that the likelihood of finding a reason for the bleeding depends on your age (Update 2004;68:6–7, International Journal of STD and AIDS 2002;13:517–21).

In people under 40 years old, no cause can be found in about one-third and the problem usually goes away in about a month. Trauma, such as a kick in the groin, may be the reason in some of these men. In the remaining two-thirds, the cause is an infection (such as chlamydia, gonorrhoea or trichomoniasis. Over 500 people with blood in the semen were involved in the scientific studies, and cancer was not a cause in anyone under 40 years of age, which means it is very unlikely, but not impossible.

In people over the age of 40, a cause can usually be found. It might be infection or a prostate problem, or some other cause. Prostate cancer has to be considered, especially in older people, but is not a common cause of blood in the semen.

Could the blood have come from you partner, and not from you? This is particularly likely if she is at the beginning or end of her period and the bleeding is not noticeable to her. If she is not menstruating, but you think the blood is from her, she may need a check-up. Use a condom the next few times you have sex. This will enable you to examine the semen and be sure the bleeding is from you.

The male reproductive system has a lot of tubing and the source of bleeding could be anywhere in the system. If the blood is red or pink, it most probably comes from the urethra (the tube inside the penis). If it is dark, it may come from further back (such as the prostate or an area called the seminal vesicles). Because one for the most common causes is inflammation in the urethra or prostate gland, sometimes caused by an infection, it would be sensible to have a check-up at your local genitourinary medicine clinic. Otherwise, see your family doctor.