Puberty in the context of Androgen insensitivity syndrome

Coming of age is a young person's transition from being a child to being an adult. The specific age at which this transition takes place varies between societies, as does the nature of the change. It can be a simple legal convention or can be part of a ritual or spiritual event.

In the past, and in some societies today, such a change is often associated with the age of sexual maturity (puberty), especially menarche and spermarche. In others, it is associated with an age of religious responsibility.

An "old wives' tale" is a colloquial expression referring to spurious or superstitious claims. They can be said sometimes to be a type of urban legend, said to be passed down by older women to a younger generation. Such tales are considered superstition, folklore or unverified claims with exaggerated and/or inaccurate details. Old wives' tales often centre on women's traditional concerns, such as pregnancy, puberty, social relations, health, herbalism and nutrition.

A child (pl. children) is a human being between the stages of birth and puberty, or between the developmental period of infancy and puberty. The term may also refer to an unborn human being. In English-speaking countries, the legal definition of child generally refers to a minor, in this case as a person younger than the local age of majority (there are exceptions such as, for example, the consume and purchase of alcoholic beverage even after said age of majority), regardless of their physical, mental and sexual development as biological adults. Children generally have fewer rights and responsibilities than adults. They are generally classed as unable to make serious decisions.

Child may also describe a relationship with a parent (such as sons and daughters of any age) or, metaphorically, an authority figure, or signify group membership in a clan, tribe, or religion; it can also signify being strongly affected by a specific time, place, or circumstance, as in "a child of nature" or "a child of the Sixties."

Sexology is the scientific study of human sexuality, including human sexual interests, behaviors, and functions. The term sexology does not generally refer to the non-scientific study of sexuality, such as social criticism.

Sexologists apply tools from several academic fields, such as anthropology, biology, medicine, psychology, epidemiology, sociology, and criminology. Topics of study include sexual development (puberty), sexual orientation, gender identity, sexual relationships, sexual activities, paraphilias, and atypical sexual interests. It also includes the study of sexuality across the lifespan, including child sexuality, puberty, adolescent sexuality, and sexuality among the elderly. Sexology also spans sexuality among those with mental or physical disabilities. The sexological study of sexual dysfunctions and disorders, including erectile dysfunction and anorgasmia, are also mainstays.

A juvenile is an individual organism (especially an animal) that has not yet reached its adult form, sexual maturity or size. Juveniles can look very different from the adult form, particularly in colour, and may not fill the same niche as the adult form. In many organisms the juvenile has a different name from the adult (see List of animal names).

Some organisms reach sexual maturity in a short metamorphosis, such as ecdysis in many insects and some other arthropods. For others, the transition from juvenile to fully mature is a more prolonged process—puberty in humans and other species (like higher primates and whales), for example. In such cases, juveniles during this transformation are sometimes called subadults.

Pubic hair (or pubes /ˈpjuːbiːz/, /pjuːbz/) is terminal body hair that is found in the genital area and pubic region of adolescent and adult humans. The hair is located on and around the sex organs, and sometimes at the top of the inside of the thighs, even extending down the perineum, and to the anal region. Pubic hair is also found on the scrotum and base of the penile shaft (in males) and on the vulva (in females). Around the pubis bone and the mons pubis that covers it, it is known as a pubic patch, which can be styled.

Although fine vellus hair is present in the area during childhood, pubic hair is considered to be the heavier, longer, coarser hair that develops during puberty as an effect of rising levels of hormones: androgens in males and estrogens in females.

Body hair or androgenic hair is terminal hair that develops on the human body during and after puberty. It is different from head hair and also from less visible vellus hair, which is much finer and lighter in color. Growth of androgenic hair is related to the level of androgens (male hormones) and the density of androgen receptors in the dermal papillae. Both must reach a threshold for the proliferation of hair follicle cells. It occurs to varying degrees in most human populations.

From childhood onward, regardless of sex, vellus hair covers almost the entire area of the human body. Exceptions include the lips, the backs of the ears, palms of hands, soles of the feet, certain external genital areas, the navel, and scar tissue. Density of hair – i.e. the number of hair follicles per unit area of skin – varies from person to person. In many cases, areas on the human body that contain vellus hair will begin to produce darker and thicker body hair during puberty, such as the first growth of beard hair on a male and female adolescent's previously smooth chin; although it may appear thinner on the female.

Facial hair is hair grown on the face, usually on the chin, cheeks, bottom lip and upper lip region. It is typically a secondary sex characteristic of human males. Men typically start developing facial hair in the later stages of puberty or adolescence, at around fourteen years of age, and most do not finish developing a full adult beard until around sixteen or later. However, large variations can occur; boys as young as ten have also been known to develop facial hair, and some men do not produce much facial hair at all.

Men may style their facial hair into beards, moustaches, goatees or sideburns; many others completely shave their facial hair and this is referred to as being "clean-shaven". The term whiskers, when used to refer to human facial hair, indicates the hair on the chin and cheeks.

Hair removal is the deliberate removal of body hair or head hair. This process is also known as epilation or depilation.

Hair is a common feature of the human body, exhibiting considerable variation in thickness and length across different populations. Hair becomes more visible during and after puberty. Additionally, men typically exhibit thicker and more conspicuous body hair than women.Both males and females have visible body hair on the head, eyebrows, eyelashes, armpits, genital area, arms, and legs. Males and some females may also have thicker hair growth on their face, abdomen, back, buttocks, anus, areola, chest, nostrils, and ears. Hair does not generally grow on the lips, back of the ear, the underside of the hands or feet, or on certain areas of the genitalia.

Child development involves the biological, psychological and emotional changes that occur in human beings between birth and the conclusion of adolescence. It is—particularly from birth to five years— a foundation for a prosperous and sustainable society.

Childhood is divided into three stages of life which include early childhood, middle childhood, and late childhood (preadolescence). Early childhood typically ranges from infancy to the age of 5 years old. During this period, development is significant, as many of life's milestones happen during this time period such as first words, learning to crawl, and learning to walk. Middle childhood/preadolescence or ages 5–10 universally mark a distinctive period between major developmental transition points. Adolescence often begins around the onset of puberty, marked as menarche or spermarche, occurring between 10 and 12 years of age, and ends upon acquiring the age of maturity.. Adolescence is characterized by maturation of the body, increase in capacity for learning, and emergence of personal identity. Developmental change may occur as a result of genetically controlled processes, known as maturation, or environmental factors and learning, but most commonly involves an interaction between the two. Development may also occur as a result of human nature and of human ability to learn from the environment.

Menstruation (also known as a period, among other colloquial terms) is the regular discharge of blood and mucosal tissue from the inner lining of the uterus through the vagina. The menstrual cycle is characterized by the rise and fall of hormones. Menstruation is triggered by falling progesterone levels, and is a sign that pregnancy has not occurred. Feminine hygiene products are used in order to maintain hygiene during menses.

The first period, a point in time known as menarche, usually begins during puberty, between the ages of 11 and 13. However, menstruation starting as young as eight years would still be considered normal. The average age of the first period is generally later in the developing world, and earlier in the developed world. The typical length of time between the first day of one period and the first day of the next is 21 to 45 days in young women; in adults, the range is between 21 and 35 days with the average often cited as 28 days. In the largest study of menstrual app data, the mean menstrual cycle length was determined to be 29.3 days. Bleeding typically lasts two to seven days. Periods stop during pregnancy and typically do not resume during the initial months of breastfeeding. Lochia occurs after childbirth. Menstruation, and with it the possibility of pregnancy, ceases after menopause, which usually occurs between 45 and 55 years of age.

In biology, infertility is the inability of a male and female organism to reproduce. It is usually not the natural state of a healthy organism that has reached sexual maturity, so children who have not undergone puberty, which is the body's start of reproductive capacity, are excluded. It is also a normal state in women after menopause.

In humans, infertility is defined as the inability to become pregnant after at least one year of unprotected and regular sexual intercourse involving a male and female partner. There are many causes of infertility, including some that medical intervention can treat. Estimates from 1997 suggest that worldwide about five percent of all heterosexual couples have an unresolved problem with infertility. That figure has been on the rise, with the World Health Organization (WHO) reporting in 2023 that about 17.5% of people experience infertility during their lifetime, while prevalence at a given time point is 12.6%. Many more couples, however, experience involuntary childlessness for at least one year, with estimates ranging from 12% to 28%.

Adolescence (from Latin adolescere 'to mature') is a transitional stage of human physical and psychological development that generally occurs during the period from puberty to adulthood (typically corresponding to the age of majority). Adolescence is usually associated with the teenage years, but its physical, psychological or cultural expressions may begin earlier or end later. Puberty typically begins during preadolescence, particularly in females. Physical growth (particularly in males) and cognitive development can extend past the teens. Age provides only a rough marker of adolescence, and scholars have not agreed upon a precise definition. Some definitions start as early as 10 and end as late as 30. The World Health Organization definition officially designates adolescence as the phase of life from ages 10 to 19.

Menarche (/məˈnɑːrki/ mə-NAR-kee; from Ancient Greek μήν (mēn) 'month' and ἀρχή (arkhē) 'beginning') is the first menstrual cycle, or first menstrual bleeding, in female humans. From both social and medical perspectives, it is often considered the central event of female puberty, as it signals the possibility of fertility. Girls experience menarche at different ages, but the most common age is 12. Having menarche occur between the ages of 9–14 in the West is considered normal.

The timing of menarche is influenced by female biology, as well as genetic, environmental factors, and nutritional factors. The mean age of menarche has declined over the last century, but the magnitude of the decline and the factors responsible remain subjects of contention. The worldwide average age of menarche is very difficult to estimate accurately, and it varies significantly by geographical region, race, ethnicity and other characteristics, and occurs mostly during a span of ages from 8 to 16, with a small percentage of girls having menarche by age 10, and the vast majority having it by the time they were 14.There is a later age of onset in Asian populations compared to the West, but it too is changing with time. For example a Korean study in 2011 showed an overall average age of 12.7, with around 20% before age 12, and more than 90% by age 14. A Chinese study from 2014 published in Acta Paediatrica showed similar results (overall average of age 12.8 in 2005 down to age 12.3 in 2014) and a similar trend in time, but also similar findings about ethnic, cultural, and environmental effects. The average age of menarche was about 12.7 years in Canada in 2001, and 12.9 in the United Kingdom. A study of girls in Istanbul, Turkey, in 2011 found the median age at menarche to be 12.7 years. In the United States, an analysis of 10,590 women aged 15–44 taken from the 2013–2017 round of the CDC's National Survey of Family Growthfound a median age of 11.9 years (down from 12.1 in 1995), with a mean of 12.5 years (down from 12.6).

In Islamic legal terminology, bāligh (Arabic: بالغ, adult) or mukallāf (Arabic: مكلف, responsible) or muhallāq (Arabic: محلاق, tendril, mentally matured) or murāhiq (Arabic: مراهق, adolescent) or muhtalim (Arabic: محتلم, pubescent) refers to someone who has reached maturity or puberty, and has full responsibility under Islamic law.

Ejaculation is the discharge of semen (the ejaculate; normally containing sperm) from the penis through the urethra. It is the final stage and natural objective of male sexual stimulation, and an essential component of natural conception. After forming an erection, many men emit pre-ejaculatory fluid during stimulation prior to ejaculating. Ejaculation involves involuntary contractions of the pelvic floor and is normally linked with orgasm. It is a normal part of male human sexual development.

Ejaculation can occur spontaneously during sleep (a nocturnal emission or "wet dream") or in rare cases because of prostatic disease. Anejaculation is the condition of being unable to ejaculate. Dysejaculation is an ejaculation that is painful or uncomfortable. Retrograde ejaculation is the backward flow of semen from the urethra into the bladder. Premature ejaculation happens shortly after initiating sexual activity, and hinders prolonged sexual intercourse. A vasectomy alters the composition of the ejaculate as a form of birth control.

The human female reproductive system is made up of the internal and external sex organs that function in the reproduction of new offspring. The reproductive system is immature at birth and develops at puberty to be able to release matured ova from the ovaries, facilitate their fertilization, and create a protective environment for the developing fetus during pregnancy. The female reproductive tract is made of several connected internal sex organs—the vagina, uterus, and fallopian tubes—and is prone to infections. The vagina allows for sexual intercourse and childbirth, and is connected to the uterus at the cervix. The uterus (or womb) accommodates the embryo by developing the uterine lining.

The uterus also produces secretions which help the transit of sperm to the fallopian tubes, where sperm fertilize the ova. During the menstrual cycle, the ovaries release an ovum, which transits through the fallopian tube into the uterus. If an egg cell meets with sperm on its way to the uterus, a single sperm cell can enter and merge with it, creating a zygote. If no fertilization occurs, menstruation is the process by which the uterine lining is shed as blood, mucus, and tissue.