Physical development of 14-year-old girls includes the first menstruation, breast growth, accelerated growth, etc., and they may be sexually aware of the desire to socialize with the opposite sex. A 14-year-old girl has entered puberty and will experience a gradual development of her genitals, endocrine system, and physique to maturity. General development includes a thinning of the voice, a rise in pitch, and a change in height. The appearance of secondary sexual characteristics includes breast growth, genital development, the appearance of pubic and armpit hair, and the first menstruation. Some 14-year-old girls have matured sexually and are beginning to be fertile. Due to the gradual development and maturity of their bodies, 14-year-old girls begin to have a hazy sense of intimacy with the opposite sex. Parents need to guide their children correctly to help them pass through puberty smoothly. In addition, adolescent girls are prone to greater psychological changes, parents should strengthen communication and good psychological care.