When boys are in puberty, they typically do not know that they have begun to produce sperm until they experience?

The correct answer is Wet dreams or better known as Nocturnal Emission.

Wet dreams start when testosterone level starts to increase, which is related to the production of sperm. Wet dreams occurs in one's sleep, it may happen in both men and women in their puberty years, for men, they will have an orgasm in their sleep, while in women may experience wetness in their genital area or an orgasm as well.