Presence of spots of blood in the front of underwear may be due:
1. Irritation/ Inflammation of testicular vessels or the urinary tract
2. Trauma to the testicles
3. Sexually transmitted disease
4. Inflammations/ Infections of the genital tract (vas deferens, prostate or seminal vesicles)
5. Prostate cancer
Investigations like urine examination, cystoscopy
and an ultrasound scan of the pelvic & testicular area will be helpful in clinching the diagnosis.
So...it will be better to consult an Urologist
to find out the exact cause.
So that necessary management steps could be taken.
Wishing a Good Health. Let me know if I need to clarify further.
Thanks & take care.