Virilization or masculinization is the biological development of adult male characteristics in young males or females. Most of the changes of virilization are produced by androgens.
Virilization is a medical term commonly used in three medical and biology of sex contexts: prenatal biological sexual differentiation, the postnatal changes of typical chromosomal male (46, XY) puberty, and excessive androgen effects in typical chromosomal females (46, XX). It is also the intended result of androgen replacement therapy in males with delayed puberty and low testosterone.