Before the Body Changes — Puberty's First Signs and the Language Families Need

5 min read日本語版あり
Audience
Parents of children aged 6–10
Target length
~1,600 words
Status
Draft v2 (translated from Japanese v1)
Original
../189_puberty_first_signs.md

Lead

"I'll get around to that conversation eventually" — and then the physical changes arrived first. This is not an uncommon experience. From the onset of breast development () to a first period, the average interval is two to three years [1]. If those two to three years pass without a single preparatory conversation, the child may be going through the changes with surprise and anxiety as their only companions.

The same applies to boys. Men recalling first ejaculation without any warning from adults consistently describe memories of loneliness and shame. "There was never an opening" is a pattern that repeats across families.

This article focuses less on the detailed content of what to say than on something more foundational: preparing the vocabulary.

The Timeline of Puberty

Girls

Since Marshall and Tanner's foundational work in 1969, the progression of puberty in girls has been studied across many countries. The onset of breast development (B2) spans an average range of 8–13 years, with an average interval of two to three years between B2 onset and first menstruation [1]. A trend toward earlier onset of puberty has been reported in multiple countries [2], and Golub and colleagues (2008) discussed potential roles of nutrition, obesity, and endocrine-disrupting compounds [3].

is defined as onset of secondary sex characteristics before age 8 in girls. If changes appear before this threshold, a pediatric consultation is recommended.

Boys

Marshall and Tanner (1970) described the increase in testicular volume as the first sign of puberty in boys [4]. The average age for first ejaculation falls in the range of 12–14 years; voice changes begin around the same period and proceed gradually over several years. The voice does not simply "drop one day" — it alternates between registers for years before settling lower.

The growth spurt in height, which runs in parallel with pubertal progression, is one of the most tangible indicators that body changes are underway.

The Concept of Vocabulary Preparation

UNESCO's International Technical Guidance on Sexuality Education ( or Comprehensive Sexuality Education) recommends that children from age 5–8 begin learning the correct anatomical names for body parts [5]. Using correct names is not only about medical accuracy — it sends a message to the child: "this topic can be spoken about normally." That signal matters.

By contrast, in families where words like "menstruation," "ejaculation," "penis," and "vulva" have never been spoken, children learn that these are taboo subjects. Taboo subjects are the hardest to raise when something goes wrong.

Stubbs (2008) argued that the language in which menstruation is spoken about shapes the quality of the menstrual experience itself [6]. A narrative of "menstruation is suffering" and a narrative of "menstruation is a normal physiological function" produce different coping behaviors when menstrual pain arrives. The words a family uses form attitudes.

Vocabulary Preparation for Girls

The colloquial "period" is fine to use. But being comfortable with "menstruation," "uterus," and "ovaries" alongside it means that conversations with a healthcare provider feel natural rather than awkward.

It is important to communicate in advance the difference between normal menstrual discomfort and the warning signs that justify a clinical visit: pain so severe the person cannot move, nausea, or an inability to carry out daily activities. can begin in adolescence — sometimes even in the school years — not only in adulthood. Communicating "severe pain warrants a visit to the doctor" early shapes future help-seeking behavior.

Discussing the range of products available — pads, tampons, menstrual cups — and having spare supplies ready in a school bag or locker before a first period arrives is a practical preparation worth walking through in conversation.

Vocabulary Preparation for Boys

Telling a boy, in advance, that ejaculation will happen — framing it as something that will occur — removes the experience from the territory of shock and isolation. Pairing a one-line "this is normal" with a practical conversation about what to do (laundry, sheets) makes the preparation usable.

Explaining the why behind voice changes and the growth spurt — once, in advance — allows a child to approach their own physical changes with understanding rather than confusion.

Assigning the sexuality conversation entirely to a same-gender parent creates a risk of severing a child's connection with the other parent. The preferred arrangement is one in which either parent can raise the topic, or both can do so together.

Deciding on a Starting Point

Rather than waiting indefinitely for the right opening, choosing a concrete trigger — "when Tanner B2 appears," "when the child enters fourth grade" — makes it more likely that the conversation actually happens.

What preparation requires is not a perfect explanation. It is the atmosphere at home that says "this subject can be raised openly." A single thorough explanation is less useful than a series of brief, recurring exchanges. The child's understanding and sense of security develop through repetition, not through a single complete account.

Three Things to Start Today

  1. Vocabulary check: Can you use "menstruation," "ejaculation," "penis," "vulva," "uterus," and "ovaries" in conversation without discomfort? If any of these feel difficult, practice saying them aloud — starting with yourself.
  2. Set a starting point: "When Tanner B2 appears" or "when the child turns 10" — pick a concrete trigger.
  3. Give the warning signs early: "If the pain is so bad you can't move, that's a reason to see a doctor" — communicate this before a first period arrives.

Summary

The body changes on its own schedule, without the child's consent. What families can prepare is vocabulary and atmosphere.

"How to say it" matters less than building the kind of relationship in which it can be said at all. The conversations about puberty are not a single event — they are a thread that runs alongside the child's physical development for several years. A relationship in which those conversations can happen, again and again, is the place a child turns when something is hard.

References

  1. Marshall WA, Tanner JM. Variations in pattern of pubertal changes in girls. Arch Dis Child. 1969;44(235):291–303. doi:10.1136/adc.44.235.291. PMID: 5785179
  2. Golub MS, Collman GW, Foster PM, et al. Public health implications of altered puberty timing. Pediatrics. 2008;121(Suppl 3):S218–S230. doi:10.1542/peds.2007-1813G. PMID: 18245512
  3. Teilmann G, Pedersen CB, Jensen TK, Skakkebaek NE, Juul A. Prevalence and incidence rate of true precocious puberty: a population based study of 1,046 cases. Int J Androl. 2005;28(Suppl 2):51. doi:10.1111/j.1365-2605.2005.00569.x
  4. Marshall WA, Tanner JM. Variations in the pattern of pubertal changes in boys. Arch Dis Child. 1970;45(239):13–23. doi:10.1136/adc.45.239.13. PMID: 5440182
  5. UNESCO. International Technical Guidance on Sexuality Education: An Evidence-Informed Approach (Revised ed). Paris: UNESCO; 2018. Available from: https://unesdoc.unesco.org/ark:/48223/pf0000260770
  6. Stubbs ML. Cultural perceptions and practices around menarche and adolescent menstruation in the United States. Ann N Y Acad Sci. 2008;1135:58–66. doi:10.1196/annals.1429.008. PMID: 18574213

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