The clitoris of a 12-year-old girl may be a normal physiological phenomenon, or it may be localized friction stimulation, or it may be due to localized infections or allergies and other factors. 1. Physiological phenomenon: 12-year-old girls may have entered the pubertal development period, genital development, clitoral size itself individual differences, so it may be manifested as the phenomenon of clitoral overgrowth. There is no other discomfort, no need for treatment. 2. Local friction stimulation: for example, wearing tight clothes local friction stimulation, or masturbation and other bad behavior. This may lead to localized edema, which may be manifested as overgrown clitoris. 3. Local infection or allergy: bacterial infection of the vulva may cause inflammatory swelling, resulting in clitoral overgrowth, in addition, local skin allergic reaction, may also cause congestion and swelling, itching, resulting in clitoral overgrowth. The 12-year-old girl’s clitoris is too long, there may be other reasons, you need to go to the regular hospital in time to check, clear the cause of the disease and follow the doctor’s instructions for treatment.