CBSE Important Questions Class 12 Biology Chapter 3 – Reproductive Health

Class 12 Biology Chapter 3 Reproductive Health is the third chapter of the NCERT Class 12 Biology textbook. It explains what reproductive health means, population growth and the need for family planning, the different birth control methods (barriers, IUDs, oral pills, sterilisation and emergency contraceptives), medical termination of pregnancy, sexually transmitted diseases (STDs), infertility and assisted reproductive technologies such as IVF (test tube baby).

These CBSE important questions for Class 12 Biology Chapter 3 cover amniocentesis and the ban on its misuse for sex determination, STDs and how to prevent them, the test tube baby method, a case study on population growth rate, MMR and IMR, and a case study on choosing the right contraceptive method for different patients. The set has multiple-choice, short-answer and case-based questions with answers for students revising for the board exam.

Q1. Amniocentesis is a prenatal diagnostic technique. While it is useful for detecting certain conditions, its use is legally restricted in India. Explain the medical application of amniocentesis and the reason for the statutory ban on its misuse.

Answer: Amniocentesis is a prenatal diagnostic test used to detect genetic disorders and chromosomal abnormalities in a developing foetus. The procedure involves collecting a small sample of amniotic fluid, which contains foetal cells. These cells are then cultured and analysed to identify conditions like Down's syndrome, haemophilia and sickle-cell anaemia.
However, this technique can also be used to determine the sex of the foetus (XX for female, XY for male). Due to a strong preference for male children in certain parts of Indian society, this capability was widely misused for sex-selective female foeticide, leading to a skewed sex ratio. To curb this unethical practice, the Indian government imposed a statutory ban on the use of amniocentesis for sex determination. The ban is specifically against its misuse for sex determination; it remains a legal and valuable tool for diagnosing genetic disorders.

Q2. From the following options, which STD is caused by bacteria?
(a) AIDS
(b) Syphilis
(c) Genital herpes
(d) Hepatitis-B

Answer: (b) Syphilis
Syphilis is caused by the bacterium Treponema pallidum. The other three are caused by viruses: AIDS by HIV, genital herpes by the herpes simplex virus and hepatitis-B by the hepatitis B virus.

Q3. What are the measures one has to take to prevent contracting STDs?

Answer: Sexually transmitted diseases (STDs) are diseases or infections which are transmitted through sexual intercourse and are caused by viruses and bacteria. Humans do not have a good level of immunity to any of the STDs. Early symptoms are mild, but if left untreated they result in serious complications later. Thus, STDs are a major threat to a healthy society. Prevention is the best cure for not contracting STDs. Some simple measures that should be taken to prevent STDs are:
1. Information and knowledge of the facts related to STDs.
2. Avoiding sex with unknown partners or multiple partners.
3. Using condoms during coitus (intercourse).
4. Immediately visiting a qualified doctor for early detection and taking complete treatment if diagnosed with the disease.

Q4. Venereal diseases are the diseases of the reproductive tract and they
(a) exist since birth.
(b) develop due to some deficiencies.
(c) spread from the intestinal infections.
(d) are sexually transmitted.

Answer: (d) are sexually transmitted.
Venereal diseases, also called sexually transmitted infections (STIs), are caused by pathogens that spread through sexual contact and affect the reproductive tract. They are not present at birth, are not caused by deficiencies, and do not spread from intestinal infections.

Q5. Describe the popular method ‘Test Tube Baby’ to overcome the problem of infertility.

Answer: Test tube baby is one of the methods of producing babies outside the body of the female. The technique is also known as in vitro fertilisation (IVF). Fertilisation is performed outside the body, after which the embryo is transferred into the body of the female. It is an assisted reproductive technology used as a remedy for infertility. It involves the following steps:
1. Collection of gametes: Ova are collected from the donor female (after hormonal treatment to produce mature ova) and sperms from the donor male.
2. In vitro fertilisation: The sperms and ova are made to fuse under simulated conditions in the laboratory (test tube or petri dish) in a fluid medium similar to the one in the womb, to form a zygote.
3. Transfer into the female: The zygote or the early embryo is transferred into the body of the female. An embryo at the 8-blastomere stage is transferred into the fallopian tube (ZIFT – zygote intrafallopian transfer). An embryo of more than 8 cells is transferred into the uterus (IUT – intrauterine transfer) for further normal development.

Q6. Analyse the observations of the case study given below.

Decade Population Growth Rate MMR (per 1,00,000) IMR (per 1,000) Contraceptive Prevalence
1981–1991 2.14% 556 80 41%
1991–2001 1.93% 407 63 49%
2001–2011 1.64% 254 44 56%

6.1. The growth rate is declining across all three decades, yet the absolute population is still rising. A student concludes that the contraceptive programme has failed. What is the flaw in this reasoning?
6.2. MMR and IMR both decline steeply, indicating public health successes. A researcher argues that these declines directly contributed to population growth. Construct this argument and explain the paradox.
6.3. Contraceptive prevalence rose by 15 percentage points, yet the growth rate fell by only 0.5 percentage points. A policymaker says the programme had low impact. A demographer disagrees. What specific demographic factor was simultaneously counteracting the effect of rising contraceptive use?

Answer: 6.1. The flaw is confusing a declining growth rate with a declining total population. A lower growth rate still means the population is increasing, only more slowly. So the contraceptive programme may still be effective even though the absolute population continues to rise.
6.2. Lower MMR (maternal mortality rate) and IMR (infant mortality rate) mean more mothers survive childbirth and more infants survive early life. This increases the number of people added to the population. The paradox is that better healthcare is a success, but in the short term it can also contribute to population growth by reducing deaths.
6.3. The key counteracting factor was the large reproductive-age population, or population momentum. Even with greater contraceptive use, if many people are in the child-bearing age group, births remain high enough to slow the fall in the growth rate.

Q7. In a study it was analysed that different patients require different contraceptive methods in different situations. Analyse the observations of a few patients and answer the questions.

Patient Age & Gender Situation Method Advised
A 22F New partner, not in a stable relationship Condom
B 32F Two children, no more wanted Partner's vasectomy
C 28F Hormonal imbalance, irregular cycle; wants to delay pregnancy Copper IUD
D 19F Unprotected intercourse 48 hours ago Emergency contraceptive

7.1. Patient A is advised condoms despite more efficient options being available. The choice is not based on contraceptive efficiency. What specific advantage of condoms justifies this recommendation?
7.2. Patient B's partner undergoes vasectomy. His first post-surgery semen sample still contains live sperms. A student says the vasectomy has failed. The doctor disagrees. Explain why sperm presence immediately after vasectomy does not indicate surgical failure.

Answer: 7.1. Condoms provide protection against sexually transmitted infections (STIs), which is crucial in a new or non-stable relationship. No other contraceptive method gives this protection.
7.2. Sperms may still be present because stored sperms remain in the vas deferens beyond the site of ligation. It takes time (several ejaculations) to clear them, so their presence immediately after surgery does not indicate failure of the vasectomy.

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