Q.Name a human genetic disorder due to the following :
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🔒 Start your 14-day free trial to unlock the full solution →Part (a)Concept understanding — Sex Determination — Ethics and Social Misuse
Sex Determination Ethics: A First Look
Imagine a family waiting for a baby. Relatives whisper, "Hope it's a boy" or "Thank God it's a girl." That casual reaction carries a heavy ethical weight. Sex determination ethics is the study of the moral questions surrounding the practice of choosing or knowing the sex of a child before birth, and the social consequences that follow.
The Core Idea
At its simplest, sex determination ethics examines whether it is morally right to use medical technology to find out whether an unborn baby is male or female, and then to act on that information — especially by aborting a fetus of the "unwanted" sex. The ethical problem is not about the technology itself (ultrasound, amniocentesis), but about what people do with that knowledge.
The NCERT textbook for Class 12 (Biology, Chapter 4: Reproductive Health) states this clearly: "Amniocentesis — a technique to determine the sex of the unborn child — is being misused to kill the female foetuses." The textbook calls this a "severe" misuse and links it directly to the declining child sex ratio in India.
Why Does This Become an Ethical Issue?
Three things make sex determination an ethical problem, not just a medical one:
- Discrimination against females. The practice is overwhelmingly used to abort female fetuses. This treats being female as a defect or a burden, which is a form of gender-based violence before birth.
- Social imbalance. When many more boys are born than girls, society faces a shortage of women. This leads to forced marriages, trafficking, and increased violence against women. The NCERT notes that the child sex ratio in India has dropped alarmingly — from 945 females per 1000 males in 1991 to 919 in 2011.
- Violation of the child's right to exist. The fetus is not given a chance to live simply because of its sex. This raises deep questions about equality and the value of every human life.
The Indian government made sex determination illegal under the Pre-Conception and Pre-Natal Diagnostic Techniques (PCPNDT) Act, 1994. This law bans doctors from telling parents the sex of the fetus, and bans any advertisement or test done solely for sex selection. Violation can lead to imprisonment and heavy fines.
The Everyday Intuition
Think of it this way: if you were told that your school would only admit boys next year, you would immediately see that as unfair. Sex determination ethics extends that same intuition to the womb. It asks: Is it fair to decide that a girl should not be born, simply because she is a girl?
The answer, from an ethical standpoint, is no. Every child — boy or girl — has equal moral worth. Using technology to eliminate an entire sex is a form of systematic discrimination that harms individuals and destabilises society.
Why It Matters for a Commerce/Humanities Student
You might think this is a "science topic," but it is deeply connected to what you study:
- Economics: A skewed sex ratio affects labour markets, marriage markets, and long-term economic growth. Fewer women mean fewer workers, consumers, and entrepreneurs.
- Political Science: Laws like the PCPNDT Act are examples of the state intervening to protect fundamental rights (right to life, right to equality). You can analyse how effective such laws are.
- Sociology: Sex determination reflects deep-rooted patriarchy, son preference, and dowry practices. It is a case study in how social norms shape — and are shaped by — technology.
- Ethics (if you study it): This is a classic dilemma: individual choice (parents wanting a son) versus social good (gender balance). Where do you draw the line?
A Few Key Points to Remember …
Part (b)Concept understanding — Mendelian Genetics Basics
Mendelian Genetics Basics
Imagine you have a box of coloured beads — red and white. If you pick one bead from the box, you get either red or white. Now imagine that the colour of your eyes, or the shape of your earlobe, is decided by something like that: a tiny "packet" inside your cells that comes in two versions, and you inherit one from each parent. That is the core idea of Mendelian genetics.
The everyday intuition
You have probably noticed that children often look like their parents — same hair colour, same dimples, same height. But they are never exact copies. Why? Because each parent contributes half of the "instructions" for building a child. Those instructions come in pairs, one from mother and one from father. Sometimes one instruction overrides the other; sometimes they blend. Gregor Mendel, a 19th-century monk, figured out the rules by watching pea plants — tall vs short, yellow vs green seeds — and counting what appeared in the next generation.
The precise meaning
Mendelian genetics is the study of how traits are passed from parents to offspring through genes. A gene is a unit of heredity — a stretch of DNA that codes for a specific characteristic, like flower colour. Each gene comes in different versions called alleles. For every gene, you inherit two alleles: one from your mother, one from your father.
If the two alleles are identical, you are homozygous for that trait. If they are different, you are heterozygous. In a heterozygous pair, one allele may be dominant — it shows up in the appearance — and the other recessive — it stays hidden unless both alleles are recessive.
Mendel's key insight was that traits are not blended like paint. Instead, alleles remain separate and are passed on intact. A recessive allele can skip a generation and reappear later, unchanged.
Why it matters
Mendelian genetics is the foundation of modern biology. It explains:
- Why some diseases run in families (like cystic fibrosis or sickle-cell anaemia)
- How plant and animal breeders create new varieties
- Why you might have your grandmother's eyes but not your mother's
The NCERT textbook states that Mendel's work established the laws of inheritance — the Law of Dominance, the Law of Segregation, and the Law of Independent Assortment. These laws describe how alleles separate during the formation of eggs and sperm, and how different genes are inherited independently of one another.
Key terms at a glance
- Gene: a unit of heredity on a chromosome
- Allele: a variant form of a gene
- Dominant: the allele that expresses itself even when paired with a different allele
- Recessive: the allele that expresses itself only when paired with an identical recessive allele
- Homozygous: having two identical alleles for a gene
- Heterozygous: having two different alleles for a gene …
Part (a)
(a) Additional X-chromosome in a male (47, XXY): Klinefelter's syndrome. …
Part (a): additional X in a male → Klinefelter's syndrome (XXY); loss of an X in a female → Turner's syndrome (XO).
Part (b): aneuploidy → genetic disorders / developmental abnormalities from unbalanced chromosome number.
Part (a)
A normal human has 46 chromosomes (23 pairs); errors in chromosome number cause specific syndromes.
- (a) An additional X-chromosome in a male gives a karyotype of 47, XXY. This causes Klinefelter's syndrome — the individual is phenotypically male but often shows some feminine features (e.g. gynaecomastia), small testes and sterility. …
- AHSEC Higher Secondary (HS) Final Examination 2024Set ANNUAL1 markQ.Fill in the blank: __________ was known as father of genetics.
›Reveal solutionSolution
Gregor Mendel, through his pea-plant hybridisation experiments, laid the foundation of the science of genetics and is honoured as its father.
Gregor Johann Mendel, an Austrian monk, conducted systematic hybridisation experiments on garden pea (Pisum sativum) between 1856 and 1863. Through careful, quantitative analysis of several contrasting traits over multiple generations, he formulated the fundamental laws of inheritance — the Law of Dominance, the Law of Segregation, and the Law of Independent Assortment — which explained how traits are passed from parents to offspring in predictable, statistically analysable ratios. Although his work (published in 1865) wa …
- AHSEC Higher Secondary (HS) Final Examination 2018Set ANNUAL1 markQ.Fill in the blank (any two of a-d):(b) The genes located in Y chromosome are called ____.
›Reveal solutionSolution
The blank is filled by holandric (Y-linked) genes.
The Y chromosome carries a small number of genes that have no allelic counterpart on the X chromosome. Such genes are transmitted only from father to son (never to daughters) and are called holandric genes or Y-linked genes. The traits they control appear only in males and follo …
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