Though we get matured almost 1 to 2 years after the female puberty age, its not same for everyone. It depends on various factors which may include even environmental changes, genetic influence, nutritional value, stress, physical or mental illness, social skills etc. Testosterone a hormone produced by the testis is let out into the blood, and along with this there is a rise in blood levels. This is usually produced more during the night time than day time as when we sleep at night we may be aroused with our dreams and even wake up with surprise and find out we had a wet dream. This cannot be controlled on our own and happens without our consciousness. Also some part of it gets converted into estradiol which helps in growth, bone growth and the end parts of bones. Also there is a least modest development of the breast tissue in boys. This change is known as Gynecomastia. This results in swelling behind the nipples , but this change is temporary and is the result of excess production of estradiol. Also one more hormone dihydrotestosterone which acts as a sex steroid synthesizes the prostate gland, testes , hair follicles and the adernal glands. These are the hormonal changes we even face a lot of physical changes. We should understand these changes as boys as this is not only faced by us but every boy out there. Also may seem painful , disgusting and also fill you with other expression but this is Life.