For sexual development of non-human organisms, see Sexual development of a boy 5 years maturity. Views of a Foetus in the Womb detail.
Puberty is the process of physical changes through which a child’s body matures into an adult body capable of sexual reproduction. Comprehensive sexuality education can contribute to teenager’s better understanding of this process. Approximate outline of development periods in child and teenager development. Puberty is marked in green at right. Two of the most significant differences between puberty in girls and puberty in boys are the age at which it begins, and the major sex steroids involved, the testosterones and the estrogens.
For boys, an androgen called testosterone is the principal sex hormone. While testosterone is produced, all boys’ changes are characterized as virilization, a substantial product of testosterone metabolism in males is estradiol. The hormone that dominates female development is an estrogen called estradiol. While estradiol promotes growth of the breasts and uterus, it is also the principal hormone driving the pubertal growth spurt and epiphyseal maturation and closure.
The hormonal maturation of females is considerably more complicated than in boys. The main steroid hormones, testosterone, estradiol, and progesterone as well as prolactin play important physiological functions in puberty. Gonadal steroidgenesis in girls starts with production of testosterone which is typically quickly converted to estradiol inside the ovaries. Adrenarche is sometimes accompanied by the early appearance of axillary and pubic hair. The first androgenic hair resulting from adrenarche can be also transient and disappear before the onset of true puberty. The onset of puberty is associated with high GnRH pulsing, which precedes the rise in sex hormones, LH and FSH. The cause of the GnRH rise is unknown.
Leptin might be the cause of the GnRH rise. Leptin has receptors in the hypothalamus which synthesizes GnRH. Individuals who are deficient in leptin fail to initiate puberty. Several studies about puberty have examined the effects of an early or a late onset of puberty in males and females. In general, girls who enter puberty late experience positive outcomes in adolescence and adulthood while girls who enter puberty early experience negative outcomes. Boys who have earlier pubertal timing generally have more positive outcomes in adulthood but more negative outcomes in adolescence, while the reverse is true for later pubertal timing.