What causes split urine stream?

There are many causes of urine stream splitting. In children, it is commonly due to posterior urethral valves causing difficulty in urination and urine stream splitting. In young and middle-aged adults, chronic prostatitis—including chronic nonbacterial prostatitis and chronic bacterial prostatitis—is frequently seen. In elderly men, benign prostatic hyperplasia (BPH) is common; prostate enlargement compresses the posterior urethra, leading to weak urinary stream, difficulty in urination, and urine stream splitting. Certain tumors may also cause urine stream splitting, such as bladder neck tumors or urethral tumors. It could also be due to malignant prostate tumors, such as prostate cancer.