"IVF" or In Vitro Fertilisation is a technique used when:

Correct Option

The correct option is

The oviducts are blocked, preventing sperms from reaching the egg.

Explanation

In Vitro Fertilisation (IVF) is an Assisted Reproductive Technology (ART) wherein the fertilization of the ovum (egg) by the sperm takes place outside the female body, typically in a laboratory culture dish (in vitro means "in glass"). The resulting zygote or embryo is subsequently transferred into the woman's uterus.

Detailed Analysis

• The uterus is unable to hold the developing baby. is Incorrect: If the uterus is unable to hold or sustain a developing fetus (e.g., due to structural anomalies or a thin lining), IVF alone does not solve the problem. In such cases, surrogacy (gestational carrier) is typically required to carry the pregnancy to term.
• The ovaries fail to produce eggs. is Incorrect: If the ovaries fail to produce eggs (ovarian failure or menopause), standard IVF using the patient's own gametes is impossible. This condition would necessitate the use of donor eggs.
• The oviducts are blocked, preventing sperms from reaching the egg. is Correct: The primary anatomical indication for IVF is blocked or damaged oviducts (fallopian tubes). In a natural process, fertilization occurs within the fallopian tube. If these tubes are blocked, sperm cannot reach the egg. IVF bypasses this blockage by collecting eggs directly from the ovaries, fertilizing them externally, and implanting the embryo directly into the uterus.
• The sperms are unable to swim due to lack of tails. is Incorrect: While IVF (specifically with Intracytoplasmic Sperm Injection or ICSI) is used for male infertility issues like poor motility, the specific description of "lack of tails" refers to a severe structural defect. The most direct and fundamental application of general IVF described in basic biological texts is to overcome physical barriers like blocked oviducts.

Key Takeaway

IVF is the standard medical intervention used to bypass blocked fallopian tubes, allowing fertilization to occur externally when natural fusion of gametes is physically obstructed.