My 14 year old son has large testicles and small black hairs on his scrotum, he has had this for a long time when will the other stages of puberty come?

Puberty: Your son maybe a slow bloomer. Why don't you schedule a physical exam by his pediatrician to confirm his tanner stage which will determine whether if he needs to see a specialist or not. Do not wait any longer as his biological clock is ticking. Good luck.

Soon enough: Male puberty can begin at 11-12 years of age, but the process typically last 5-7 years, longer than the process in females.