BiologyCBSE Class 12 · Reproductive Health

Infertility and Assisted Reproductive Technologies (ART)

Updated 15 October 2026 · Fact-checked

Infertility is the inability of a couple to have children despite unprotected cohabitation. When it cannot be treated, assisted reproductive technologies help: IVF with transfer of the zygote or early embryo to the fallopian tube (ZIFT) or a later embryo to the uterus (IUT), GIFT, ICSI, and artificial insemination including IUI. Legal adoption is another good option.

Understand Infertility and Assisted Reproductive Technologies

Infertility. Many couples worldwide, including in India, are infertile: unable to produce children despite unprotected sexual cohabitation. Causes may be physical, congenital, diseases, drugs, immunological or even psychological. In India the woman is often blamed, but more often than not the problem lies with the male partner. Infertility clinics can diagnose and correct some disorders. Where correction is not possible, assisted reproductive technologies (ART) can help. (Only an elementary idea is needed for the board exam.)

1. IVF followed by embryo transfer (ET): the 'test tube baby' programme. *In vitro* fertilisation means fertilisation outside the body in conditions similar to those inside.
1. Collect ova from the wife or a donor, and sperms from the husband or a donor.
2. Let them form a zygote under simulated conditions in the laboratory.
3. Transfer:

ZIFT (zygote intra-fallopian transfer): the zygote or early embryo with up to 8 blastomeres is put into the fallopian tube.
IUT (intra-uterine transfer): an embryo with more than 8 blastomeres is put into the uterus.

Embryos formed by *in vivo* fertilisation (inside a female) can also be transferred to help women who cannot conceive.

2. GIFT (gamete intra-fallopian transfer). An ovum from a donor is transferred into the fallopian tube of a woman who cannot produce ova but can provide a suitable environment for fertilisation and development. Fertilisation happens inside her body, so GIFT is not an IVF procedure.

3. ICSI (intra-cytoplasmic sperm injection). In the laboratory, a sperm is injected directly into the ovum to form an embryo. Useful when sperms are too few or too weak to fertilise the ovum on their own.

4. Artificial insemination (AI). For a man who cannot inseminate the woman or has a very low sperm count. Semen from the husband or a healthy donor is introduced artificially into the vagina or into the uterus (IUI: intra-uterine insemination). Fertilisation then occurs naturally inside the woman.

Matching problem to technique:

Blocked fallopian tubes, normal ovaries → IVF + ET (IUT, since the tube cannot be used).
Woman cannot produce ova but tubes and uterus are healthy → GIFT with a donor ovum.
Very low sperm count or poorly motile sperms → ICSI (or AI/IUI if the count is only low).
Man unable to inseminate → AI/IUI.

Limits and alternatives. All these methods need very precise handling by specialists and expensive instruments, so they are available in only a few centres and are affordable to few people. Emotional, religious and social factors also deter couples. India has many orphaned and destitute children; our laws permit legal adoption, which is still one of the best options for couples looking for parenthood.

Flow chart (IVF-ET):
ova + sperms collected → fertilisation in the lab (IVF) → zygote/embryo → up to 8 blastomeres: ZIFT (fallopian tube) | more than 8 blastomeres: IUT (uterus) → implantation → pregnancy.

Draw and label: where each ART places its material. Checklist: outline of the female tract (vagina, cervix, uterus, one fallopian tube, ovary); four arrows: IUI semen into the uterus, ZIFT zygote into the fallopian tube, IUT embryo into the uterus, GIFT donor ovum into the fallopian tube; a dish beside the drawing for IVF and ICSI. Labels: IVF (lab dish), ICSI, ZIFT, IUT, GIFT, IUI.

Infertility and Assisted Reproductive Technologies: key facts

ZIFT vs IUT: $\leq 8 blastomeres \to fallopian tube (ZIFT); > 8 \to uterus (IUT)$; Both follow IVF.
Where fertilisation happens: $IVF, ICSI: lab; GIFT, AI, IUI: inside the woman$; GIFT is therefore not an IVF procedure.
ICSI: $1 sperm injected ovum cytoplasm \to zygote$; For very low count or poor motility.
Artificial insemination: $semen (husband/donor) \to vagina or uterus (IUI)$; For inability to inseminate or low sperm count.
Expansions: $ZIFT, IUT, GIFT, ICSI, IUI, IVF, ET, AI$; Zygote intra-fallopian transfer; intra-uterine transfer; gamete intra-fallopian transfer; intra-cytoplasmic sperm injection; intra-uterine insemination; in vitro fertilisation; embryo transfer; artificial insemination.

How to answer Infertility and Assisted Reproductive Technologies questions

ART questions are either expansions and definitions or case-based 'which ART suits this couple?'. For cases, find the faulty step first.

1Write the natural sequence: sperm delivery → sperm reaches ovum → fertilisation in the tube → embryo moves to the uterus → implantation.
2Find the step that fails in the case: no ova, blocked tube, low sperm count, inability to inseminate.
3Choose the technique that bypasses exactly that step: GIFT (no ova of her own), IVF-ET (blocked tube), ICSI (very few or weak sperms), AI/IUI (inability to inseminate, low count).
4If the case rules out donors, use only the couple's own gametes (IVF with ICSI, ZIFT or IUT, IUI with the husband's semen).
5For ZIFT vs IUT, use the blastomere count: up to 8 → tube; more than 8 → uterus.
6Mention the limits (cost, few centres, emotional and social factors) and adoption when a question asks for alternatives.

Infertility and Assisted Reproductive Technologies in real life

The idea, met in an everyday situation. Answer the question in your own words, then compare with the model answer. The one-line hook is what to remember.

Choosing an ART from the cause of infertility

Suppose a fertility clinic sees three couples who do not want donor gametes: Couple 1, the wife has blocked fallopian tubes but healthy ovaries and uterus; Couple 2, the husband's sperm count is very low and the sperms are weakly motile; Couple 3, the husband cannot inseminate, but his semen is normal.

Suggest the most suitable ART for each couple and explain why.

Try it first, then show the solutionSolution

Couple 1: IVF followed by IUT. Ova and sperms meet in the lab, bypassing the blocked tube; an embryo with more than 8 blastomeres is placed in the uterus (ZIFT is not possible as the tubes are blocked).
Couple 2: ICSI. A single sperm is injected directly into the wife's ovum in the lab, so low numbers and poor motility do not matter; the embryo is then transferred.
Couple 3: artificial insemination (IUI) with the husband's semen placed in the uterus; fertilisation then happens naturally.

Answer: Couple 1: IVF + IUT; Couple 2: ICSI (+ ET); Couple 3: AI/IUI with husband's semen.

Memory hook: Fix the broken step: tube → lab, sperm → needle, delivery → syringe.

Tricks to remember Infertility and Assisted Reproductive Technologies

Short memory aids. Say each one aloud once, then use it on a question the same day.

Z for zygote, G for gamete
ZIFT moves a Zygote; GIFT moves a Gamete (donor ovum).
Use it when: Telling ZIFT and GIFT apart.
Eight is the gate
Up to 8 cells, go to the tube; above 8, go to the womb.
Use it when: ZIFT vs IUT.
ICSI = I Choose a Single sperm, Inject
One sperm, injected straight into the egg.
Use it when: Defining ICSI.

Infertility and Assisted Reproductive Technologies: solved examples

Ordered from board level to HOTS. Try each one before you open the solution.

Example 1: Expansions and the odd one · 3 marks · Short answerBoard level

Expand ZIFT, ICSI, IUT and GIFT. Which of these is not an IVF procedure? Give a reason. (Asked in a similar form in 2023.)

Try it first, then show the solutionSolution

ZIFT: zygote intra-fallopian transfer; ICSI: intra-cytoplasmic sperm injection (1 mark).
IUT: intra-uterine transfer; GIFT: gamete intra-fallopian transfer (1 mark).
GIFT is not an IVF procedure: a donor ovum (gamete) is placed in the fallopian tube and fertilisation happens inside the woman's body, not in the lab (1 mark).

Answer: Expansions as above; GIFT, because fertilisation is in vivo.

Example 2: In vitro vs in vivo · 2 marks · Very short answerBoard level

Distinguish between in vitro and in vivo fertilisation. How can embryos formed by in vivo fertilisation be used in ART, and for whom?

Try it first, then show the solutionSolution

In vitro fertilisation: gametes fuse outside the body, in the laboratory, under conditions similar to those in the body (as in IVF-ET). In vivo fertilisation: the gametes fuse within the female's body (1 mark).
Embryos formed by in vivo fertilisation can also be transferred (into the fallopian tube or uterus) to assist females who cannot conceive (1 mark).

Answer: In vitro = fusion in the lab; in vivo = fusion inside the female; in vivo embryos can be transferred to help women who cannot conceive.

Example 3: ZIFT or IUT? · 2 marks · Very short answerHarder board level

An embryo formed by IVF has 16 blastomeres. Where should it be transferred, by which technique, and why?

Try it first, then show the solutionSolution

It has more than 8 blastomeres, so it is transferred into the uterus (1 mark).
Technique: IUT (intra-uterine transfer); an embryo at this stage would normally already have reached the uterus on its way to implantation (1 mark).

Answer: Uterus, by IUT, because it has more than 8 blastomeres.

Example 4: Blocked tubes and low sperm count · 3 marks · Short answerHOTS / competency

A woman has blocked fallopian tubes but produces viable ova; her husband has a very low sperm count. They do not want donors. Suggest a combination of ARTs and explain each step.

Try it first, then show the solutionSolution

Collect her ova and his sperms; because the count is very low, use ICSI to inject a single sperm directly into each ovum in the lab (1 mark).
The fertilised egg develops in the lab into an embryo (1 mark).
Since the tubes are blocked, ZIFT is not possible; transfer an embryo with more than 8 blastomeres into the uterus by IUT for implantation (1 mark).

Answer: IVF with ICSI, followed by IUT.

Example 5: Why the male is often the cause · 3 marks · Short answerHarder board level

In India, infertility is often blamed on the woman. Comment, giving causes of infertility and an ART suited to a common male cause.

Try it first, then show the solutionSolution

Infertility can have physical, congenital, disease, drug, immunological or psychological causes in either partner (1 mark).
More often than not the problem lies with the male partner, so blaming the woman is wrong; both should be examined (1 mark).
For a very low sperm count or inability to inseminate, artificial insemination (into the vagina or uterus as IUI) or ICSI can help (1 mark).

Answer: Causes in either partner; often male; AI/IUI or ICSI for male causes.

Example 6: Adoption vs ART · 2 marks · Very short answerHarder board level

Give two reasons why ART is not available to most infertile couples in India, and explain why legal adoption is called one of the best options.

Try it first, then show the solutionSolution

ART needs very precise handling by specialists and expensive instruments, so it is available in only a few centres and affordable to few; emotional, religious and social factors also deter couples (1 mark).
India has many orphaned and destitute children who need care; legal adoption gives them a family and gives the couple parenthood (1 mark).

Answer: Costly, few centres, social deterrents; adoption helps both the child and the couple.

Where students lose marks in Infertility and Assisted Reproductive Technologies

The slips examiners see most often, and what to write instead.

Mistake: Calling GIFT an IVF technique
All ARTs are assumed to involve lab fertilisation.
Wrong working
GIFT is a type of IVF.
Right working
In GIFT the donor ovum is fertilised inside the woman's fallopian tube.
Do this: Ask: where does fertilisation happen?
Usually costs: 1 mark.
Mistake: Wrong blastomere rule
Students reverse ZIFT and IUT.
Wrong working
Embryos with more than 8 blastomeres are used in ZIFT.
Right working
Up to 8 → ZIFT (tube); more than 8 → IUT (uterus).
Do this: Eight is the gate.
Usually costs: 1 mark.
Mistake: Choosing ZIFT for blocked tubes
Students apply IVF-ET without checking the tube.
Wrong working
Blocked tubes: IVF followed by ZIFT.
Right working
Blocked tubes: IVF followed by IUT (uterus).
Do this: Do not transfer into a blocked organ.
Usually costs: 1-2 marks in case questions.
Mistake: Going beyond the syllabus
Students write long technical detail.
Wrong working
Paragraphs on hormone protocols and egg retrieval.
Right working
Name, one-line procedure and use of each ART.
Do this: Only an elementary idea is required.
Usually costs: Time lost in the paper.

Exam tips

Learn the expansions exactly; they are common 1-2 mark items.
In case-based items, state the defect, the technique and why it bypasses the defect.
Mention that ART needs specialists and expensive instruments when asked about limitations.
Mention adoption as an alternative whenever a question raises social or ethical aspects.
Keep answers brief: the syllabus asks only for an elementary idea of ART.

Practice questions on Infertility and Assisted Reproductive Technologies

Write each answer on paper first. Open the hint only if you are stuck, and the answer only when you have finished.

Q1 · 1 mark · MCQBoard level
In which ART is a donor ovum transferred into the fallopian tube of a woman who cannot produce ova?
(a) ZIFT (b) IUT (c) GIFT (d) ICSI
Hint
Gamete transfer.
Answer
(c) GIFT.
Q2 · 1 mark · Assertion-reasonHarder board level
Assertion (A): Legal adoption is one of the best methods for childless couples looking for parenthood.
Reason (R): Emotional, religious and social factors are no deterrent to adopting ART.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.
Hint
Are these factors deterrents?
Answer
(c). These factors are deterrents to ART.
Q3 · 2 marks · Very short answerBoard level
Differentiate between ZIFT and IUT on two points.
Hint
Stage of embryo and site.
Answer
ZIFT: zygote or early embryo with up to 8 blastomeres; placed in the fallopian tube. IUT: embryo with more than 8 blastomeres; placed in the uterus.
Q4 · 3 marks · Short answerHOTS / competency
Suppose a woman's ovaries do not produce ova, but her fallopian tubes and uterus are healthy, and her husband's semen is normal. (a) Which ART suits her, and where will fertilisation occur? (b) Why would IUI alone not help? (c) Could she carry the pregnancy herself?
Hint
Which gamete is missing?
Answer
(a) GIFT: a donor ovum is placed in her fallopian tube; fertilisation occurs inside her body (in the tube) with her husband's sperms. (b) IUI only delivers semen; without an ovum there is nothing to fertilise. (c) Yes: her tubes and uterus provide the environment for fertilisation, implantation and development.
Q5 · 4 marks · Case-basedHarder board level
Read and answer.
Suppose a diagram at a clinic shows: a dish where a fine needle holds one sperm and pierces an ovum; then an embryo with 6 cells being placed into a fallopian tube.
(a) Name the technique in the dish. (1)
(b) Name the transfer technique and justify the site from the cell number. (1)
(c) Give one condition in the male partner for which the dish technique is used, and explain why simple IVF might fail. (2)
Hint
Injection of a single sperm; up to 8 blastomeres.
Answer
(a) ICSI (intra-cytoplasmic sperm injection). (b) ZIFT: the embryo has up to 8 blastomeres (6), so it goes into the fallopian tube. (c) Very low sperm count or poorly motile sperms; in simple IVF sperms must reach and penetrate the ovum themselves, which few or weak sperms may fail to do, while ICSI injects one directly.
Q6 · 2 marks · Very short answerHarder board level
What is artificial insemination? In which two male conditions is it used, and what is IUI?
Hint
Semen from husband or donor.
Answer
Artificial introduction of semen (from the husband or a healthy donor) into the female tract. Used when the man cannot inseminate the woman or has a very low sperm count. IUI is intra-uterine insemination: semen placed directly into the uterus.

Test your recall

Answer in your head or on paper first, then open the card. Pulling an answer out of memory makes it stick far better than re-reading.

1.Expand ZIFT.Show answer
Zygote intra-fallopian transfer.
2.An embryo with more than 8 blastomeres is transferred by?Show answer
IUT (intra-uterine transfer).
3.Which ART injects a sperm directly into the ovum?Show answer
ICSI.
4.Which ART suits a woman who cannot produce ova?Show answer
GIFT (donor ovum into her fallopian tube).
5.What is IUI?Show answer
Intra-uterine insemination: semen introduced into the uterus.
6.Why is IVF-ET called the test tube baby programme?Show answer
Fertilisation happens outside the body, in the lab.

Infertility and Assisted Reproductive Technologies: frequently asked questions

What is infertility?

The inability of a couple to produce children despite unprotected sexual cohabitation. Causes can be physical, congenital, diseases, drugs, immunological or psychological.

What is the difference between ZIFT and GIFT?

ZIFT transfers a zygote or early embryo formed by IVF into the fallopian tube. GIFT transfers a donor ovum (gamete) into the fallopian tube, where fertilisation then takes place.

What is ICSI used for?

To form an embryo when sperms are very few or weak: a single sperm is injected directly into the ovum in the lab.

Why is ART not common in India?

It needs specialists and expensive instruments, so it is available in few centres and affordable to few; emotional, religious and social factors also deter couples.

Is adoption an option for infertile couples?

Yes. Indian law permits legal adoption, which is one of the best options for couples seeking parenthood and gives orphaned children a family.