Prostatitis: This is often the most common cause of hematospermia (blood in the ejaculate), particularly in younger men. Prostatitis, which is inflammation of the prostate gland, can be caused by bacterial or non-bacterial factors and can lead to bleeding into the ejaculatory ducts.

Benign Prostatic Hyperplasia (BPH): Enlargement of the prostate gland, common in older men, can cause bleeding due to the increased vascularity and potential for minor trauma during ejaculation.
Urethritis: Inflammation of the urethra can cause bleeding, which may then appear in the ejaculate. This can be due to infectious or non-infectious causes.
Seminal Vesiculitis: Inflammation of the seminal vesicles, which can be due to infection or other causes, may lead to bleeding into the ejaculate.

Prostate Cancer: Although less common, prostate cancer can cause hematospermia. It is crucial to rule out this potentially life-threatening condition, especially in older men or those with risk factors.
Genitourinary Trauma: Any form of trauma to the genital or urinary tract area can cause bleeding that may appear in the ejaculate. This includes iatrogenic causes, such as after a medical procedure.
Infections (e.g., Tuberculosis, STDs): Certain infections, including sexually transmitted diseases (STDs) and tuberculosis, can involve the genital tract and cause hematospermia.

Amyloidosis: A condition characterized by the deposition of amyloid (a particular type of protein) in various tissues, which can rarely affect the prostate or seminal vesicles and cause bleeding.
Vascular Malformations: Rarely, vascular abnormalities within the prostate or seminal vesicles can cause bleeding into the ejaculate.
Systemic Diseases (e.g., Bleeding Disorders): Conditions that affect the body's ability to clot blood, such as hemophilia, can lead to bleeding in various parts of the body, including into the ejaculate, though this would be extremely rare as a primary presentation.