Puberty is a critical phase, typically beginning between the ages of 8 and 13 in girls and 9 and 14 in boys, though timing can vary based on genetics, environmental factors, and overall health. This period is characterized by the development of secondary sexual characteristics and the attainment of reproductive potential. Endocrine changes underpin puberty, with hormonal surges of Luteinizing Hormone (LH) and Follicle-Stimulating Hormone (FSH) instigated by Gonadotropin-Releasing Hormone (GnRH) pulses. These pulses predominantly occur during sleep initially but gradually extend into waking hours over 3-4 years, fully activating the hypothalamic-pituitary-gonadal (HPG) axis and establishing an adult hormone secretion pattern.

In males, testosterone plays a pivotal role in puberty. It fosters the functional maturation of accessory reproductive glands, including the prostate and seminal glands, and facilitates spermatogenesis. It also promotes primary sexual characteristics, such as testicular enlargement, and secondary characteristics, including increased body and facial hair. Conversely, in females, estrogens are instrumental. They target the uterus, instigating a thickening of the myometrium, boosting endometrial blood flow, and stimulating cervical mucus production. Additionally, estrogens encourage the functional development of female accessory reproductive organs, including the breasts, fallopian tubes, and vaginal epithelium.

The onset of menstrual cycles, or menarche, doesn't immediately lead to regular ovulation. In fact, for the first 1-2 years post-menarche, ovulation occurs in a minority of cycles—often cited as approximately 10%—and the luteal phase is typically shorter than the standard 14 days. Over time, however, the percentage of ovulatory cycles increases, and the luteal phase stabilizes at a typical duration of 14 days.

Testosterone also triggers vocal changes, stimulating the growth of the larynx and the thickening and lengthening of the vocal cords, which deepens the male voice during the later stages of puberty. Sex hormones stimulate skeletal muscle growth, enhancing strength and endurance. Testosterone's effects significantly exceed those of estrogens, leading to noticeable sex differences in body mass.

Both testosterone and estrogen accelerate bone deposition and skeletal growth. However, they also promote the closure of epiphyseal cartilages, effectively capping height growth. Girls generally do not grow as tall as boys due to an earlier onset of puberty and a more rapid estrogen-induced epiphyseal cartilage closure.

Fat distribution patterns also diverge at puberty due to the effects of androgens in males and estrogens in females. Men tend to accumulate subcutaneous fat at the neck, arms, lower back, and buttocks, while women store it predominantly at the breasts, buttocks, hips, and thighs.