Uneven mixing of blood and semen may be the presence of hematospermia, which is usually associated with trauma, seminal vesiculitis, prostatitis, ductal obstruction and cysts. 1. Trauma: For example, injury to the perineum, where semen mixes with blood during ejaculation, may lead to uneven mixing of blood and semen, which may be accompanied by symptoms such as pain and localized swelling. 2. Vesiculitis: When there is vesiculitis, the blood vessels on its surface rupture and bleed, which may cause hematospermia, accompanied by symptoms such as painful ejaculation. 3. Prostatitis: when men suffer from prostatitis, the pressure inside the prostate gland can increase during sex, causing local capillaries to rupture and bleed, which may cause the ejaculated semen to mix unevenly with the blood, and is accompanied by symptoms such as swelling and pain in the perineum, frequent urination, and incomplete urination. 4. Duct obstruction and cysts: such as ejaculatory duct obstruction, ejaculatory duct cysts, etc., during ejaculation can make the local rupture and bleeding, and the blood mixes with semen, which may cause hematospermia. Uneven mixing of blood and semen indicates the presence of abnormalities, and men are advised to seek early medical examination and treatment to avoid other complications.