Human Reproduction and Growth: The Beginning of Life
BasicA scientific look at the reproductive system, puberty and how life begins.
- Reproduction needs both sexes: testis and sperm, ovary and egg.
- Puberty differs — never compare or feel awkward.
- Menstruation is healthy; keep clean, see a doctor if pain is severe.
文體小知識：科學原理課——對應科學科課程「探索生物的生殖」：以科學認識人類的生殖系統、青春期與生命誕生的過程。
§Text Passage
1Reproduction is the process by which living things produce offspring. In humans it involves both sexes: the male reproductive system's main organ, the testis, produces sperm (the male sex cell) and male hormones; the female main organ, the ovary, produces eggs (the female sex cell) and female hormones. Sperm is among the smallest cells in the body; the egg is the largest — when they meet, a new life begins.
2Puberty (roughly ages 10–18) is when the reproductive system matures and secondary sexual characteristics appear: boys' voices deepen, beards grow and shoulders widen; girls' breasts develop and menstruation begins. Menstruation is a normal monthly process showing that a mature egg was released unfertilised — a sign of health, nothing embarrassing. Fertilisation happens when a sperm meets an egg in the oviduct; the fertilised egg travels to the uterus and implants, developing over about 40 weeks (280 days) of pregnancy into a baby.
3Scientific knowledge is the first step of self-protection: everyone's puberty timetable differs, so never compare or feel awkward; keep good personal hygiene; understand that pregnancy needs a mature body and mind — an adolescent body is not fully developed; and bring any questions about your body to parents, teachers or medical professionals. Knowing your body scientifically is where respect for life begins.
1Summary 重點摘要
A scientific look at the reproductive system, puberty and how life begins.
2Vocabulary cards Vocabulary
The process of producing offspring.
The male organ producing sperm.
The female organ producing eggs.
The male sex cell.
The female sex cell.
The stage of sexual maturation.
The monthly shedding of the uterus lining.
The joining of sperm and egg.
About 280 days of development in the uterus.
3Step by step Steps
- Step 1: Two systems, two cellsThe male and female reproductive systems each have their own roles: in males the testes produce sperm and secrete male hormones; in females the ovaries produce eggs and secrete female hormones. Memorise the pairing firmly — male: testes with sperm; female: ovaries with eggs. It is the foundation of the whole reproduction topic, and the fertilisation and development that follow are all built on these two kinds of sex cells.
- Step 2: The sex cellsSperm and eggs differ greatly in structure: sperm are tiny, tail-bearing and able to swim, produced in the millions; the egg is large and round, and limited in number. Each carries half the genetic material — 23 chromosomes apiece; only after fertilisation, when they join into a fertilised egg, is the full set of 46 chromosomes restored, the genetic blueprint of the new individual completed, and the sex determined at that moment.
- Step 3: Puberty changesDuring puberty both sexes grow rapidly, develop pubic and underarm hair, and produce more skin oil, so regular cleaning matters to keep acne under control. Changes specific to boys include a deepening voice and a growing beard; girls develop breasts and begin menstruating. Everyone's developmental timetable differs — earlier or later is all normal, so there is nothing to compare and no cause for worry.
- Step 4: Menstruation is healthyMenstruation comes about once a month as part of the uterus's preparation for pregnancy: when a mature egg is released unfertilised, the uterine lining is shed and passes out of the body with some blood. It is a perfectly normal physiological process, not an illness — if anything, it shows the reproductive system is working well. Keep up personal hygiene during the period; if pain seriously disrupts daily life, tell a parent and see a doctor early.
- Step 5: Fertilisation and pregnancyFertilisation and pregnancy follow a fixed order: sperm and egg meet in the oviduct and form a fertilised egg; the fertilised egg travels to the uterus and implants; the foetus obtains oxygen and nutrients from the mother through the umbilical cord and placenta while passing wastes back; after about 280 days of pregnancy the baby is born. The mother's health and habits during pregnancy directly shape the foetus's development, which is why prenatal care matters so much.
- Step 6: Respect life and bodyThree principles must be kept in mind: first, your body belongs to you, and you have the right to refuse any contact you do not want; second, pregnancy requires a mature mind and body — adolescents are still developing and should not take on the responsibilities it brings; third, bring questions to reliable people such as parents, teachers and medical professionals. Scientific knowledge is the basis of self-protection — respect yourself and respect others.
5Worked example Example
Sample: 'Name one secondary sexual characteristic for each sex and explain why menstruation is a sign of health.'
- Step 1: Define — secondary sexual characteristics are changes linked to reproductive maturing.
- Step 2: Male — deepening voice, beard, broader shoulders (any one).
- Step 3: Female — breast development, menstruation (any one).
- Step 4: Explain — menstruation shows a mature egg was released unfertilised and the uterine lining shed normally.
- Answer: Sample answer: In boys, the voice deepens and beards grow; in girls, breasts develop and menstruation begins. Menstruation is a sign of health: it shows that a mature egg was released unfertilised and the uterine lining shed normally — the reproductive system is working well, and there is nothing embarrassing about it.
6Common mistakes Mistakes
7Quick check Quick check
Q1Which organ produces sperm?
Q2Which organ produces eggs?
Q3Where does fertilisation occur?
Q4How long is pregnancy?
Q5What does menstruation indicate?
8Recap Recap
- Reproduction needs both sexes: testis and sperm, ovary and egg.
- Puberty differs — never compare or feel awkward.
- Menstruation is healthy; keep clean, see a doctor if pain is severe.
- Fertilisation → implantation → 280 days of pregnancy.
- Scientific knowledge of your body is self-respect and self-protection.