Biology · Human Reproduction · NEET
| Number of gametes from one cell | 4 equal functional sperms | 1 functional ovum + polar bodies |
| When it begins | At puberty | During embryonic (before-birth) stage |
| Cytoplasm division | Equal | Unequal (ovum keeps most cytoplasm) |
| Continuity | Continuous once started | Discontinuous, arrested in pauses |
| New gamete mother cells after birth | Yes, spermatogonia keep dividing | No new oogonia added after birth |
| Site | Seminiferous tubules of testis | Follicles of ovary |
One primary spermatocyte gives 4 equal, functional sperms after the two meiotic divisions. One primary oocyte gives only 1 functional ovum, because each division is unequal and pushes out a tiny polar body that dies. So spermatogenesis is 1 cell to 4 gametes, but oogenesis is 1 cell to 1 gamete. This is the single most-tested difference in NEET.
Spermatogenesis begins at puberty. Oogenesis is initiated much earlier, during the embryonic development stage, when a couple of million oogonia form inside each fetal ovary. So by the time a girl is born, her oogonia are already made, but a boy's sperm-making has not even started. NEET 2022 and NEET 2025 both tested this exact start-time point.
Oogenesis is discontinuous and slow. The oogonia enter prophase-I before birth and get temporarily arrested there for years. The primary oocyte finishes meiosis I only around ovulation, and meiosis II is completed only if a sperm enters. Spermatogenesis, by contrast, runs continuously once it starts at puberty, with the stem cells (spermatogonia) dividing again and again.
No. NCERT clearly says no more oogonia are formed and added after birth in females. The full stock is fixed before birth. But in males, spermatogonia keep multiplying by mitosis throughout reproductive life, so new gamete mother cells are always available. This 'fixed stock vs endless supply' point is a favourite NTA trap.
The cytoplasm divides unequally so that one cell keeps almost all the food and cell material to become a large ovum, while the other cell becomes a tiny polar body. This saves the yolk and nutrients for the future zygote. In spermatogenesis the division is equal because a sperm does not need to store food; it only needs to swim and deliver DNA.
Both are types of gametogenesis, both use meiosis to make haploid gametes, and both are controlled by the pituitary hormones FSH and LH. Because these points are shared, NEET uses them as wrong options when it asks for a difference. Only the number of gametes, the start time, the continuity, and equal vs unequal division are true differences.
Which of the following statements are true for spermatogenesis but do not hold true for Oogenesis? (a) It results in the formation of haploid gametes (b) Differentiation of gamete occurs after the completion of meiosis (c) Meiosis occurs continuously in a mitotically dividing stem cell population (d) It is controlled by the Luteinizing hormone (LH) and Follicle Stimulating Hormone (FSH) secreted by the anterior pituitary (e) It is initiated at puberty
Consider the following: A. The reductive division for the human female gametogenesis starts earlier than that of the male gametogenesis. B. The gap between the first meiotic division and the second meiotic division is much shorter for males compared to females. C. The first polar body is associated with the formation of the primary oocyte. D. Luteinizing Hormone (LH) surge leads to disintegration of the endometrium and onset of menstrual bleeding. Choose the correct answer:
At which stage of life the oogenesis process is initiated?
Try the real previous-year questions from this chapter — each with the answer and a full solution.
One primary spermatocyte makes 4 equal functional sperms. One primary oocyte makes only 1 functional ovum, plus polar bodies that die.
Oogenesis starts first, in the embryonic (before-birth) stage. Spermatogenesis starts later, at puberty.
No. Spermatogenesis divides the cytoplasm equally. Oogenesis divides it unequally, so the ovum keeps most of the cytoplasm and the polar body gets very little.
Yes. Both spermatogenesis and oogenesis are controlled by the pituitary hormones FSH and LH. This is a similarity, not a difference, so NEET uses it as a trap option.
Spermatogenesis happens in the seminiferous tubules of the testis. Oogenesis happens inside the follicles of the ovary.
In males, meiosis runs continuously and finishes within days. In females, meiosis I completes near ovulation and meiosis II is completed only when a sperm enters the secondary oocyte.
