Spermatogenesis and oogenesis are two critical processes in the formation of male and female gametes. Spermatogenesis takes place in the male reproductive system, giving rise to sperm cells, while oogenesis occurs in the female reproductive system, resulting in the production of ova (egg cells). These processes ensure that each gamete contains half the genetic material (haploid), which is essential for fertilisation to form a diploid zygote.

In this article, we will explore the difference between spermatogenesis and oogenesis in detail. This will help you understand their roles in human reproduction comprehensively.

What is Spermatogenesis?

Spermatogenesis is the process through which haploid sperm cells are produced from diploid spermatogonia (male germ cells). It occurs in the Seminiferous Tubules of the testes and generally continues throughout the reproductive lifespan of males. The key stages are:

Multiplication Phase: Mitotic division of spermatogonia to maintain their number and produce primary spermatocytes.
Growth Phase: Primary spermatocytes grow in size and prepare for meiosis.
Maturation Phase: Primary spermatocytes undergo Meiosis I to form secondary spermatocytes, which then undergo Meiosis II to produce spermatids.
Spermiogenesis: Spermatids transform into mature spermatozoa (sperm cells) by developing a tail and condensing nuclear material.

What is Oogenesis?

Oogenesis is the process by which a mature ovum (egg cell) is formed from diploid oogonia (female germ cells) in the ovaries. It begins before a female is born and is characterised by two arrest periods:

Foetal Stage: Oogonia proliferates by mitosis, then transforms into primary oocytes. These primary oocytes remain arrested in Prophase I of meiosis until puberty.
After Puberty: Each menstrual cycle, a few primary oocytes resume development. One primary oocyte completes Meiosis I to form a secondary oocyte and a polar body. The secondary oocyte then begins Meiosis II but halts at Metaphase II.
Fertilisation: Meiosis II completes only if fertilisation by a sperm occurs, resulting in a fertilised ovum and a second polar body.

10 Differences between Spermatogenesis and Oogenesis

Point of Difference	Spermatogenesis	Oogenesis
1. Location	Occurs in the testes.	Occurs in the ovaries.
2. Stages Completion	All stages (including spermiogenesis) are completed in the testes.	The majority of early stages occur within the ovaries; the final stage completes in the Oviduct if fertilisation occurs.
3. Continuity	It is a continuous process from puberty onward.	It is a discontinuous process, starting before birth and pausing at different stages until fertilisation.
4. Cytokinesis	Cytokinesis is equal, producing four functional sperm cells.	Cytokinesis is unequal, producing one large ovum and smaller polar bodies.
5. Motility of Gametes	Sperm cells are motile.	The ovum is non-motile.
6. Quantity Produced	Millions of sperm are produced daily.	Generally, one ovum is released per menstrual cycle.
7. Growth Phase Duration	Primary spermatocytes have a shorter growth phase.	Primary oocytes have a prolonged growth phase, arrested for years (from foetal life until puberty or beyond).
8. Time Taken	It takes about 64–72 days to form mature sperm cells from spermatogonia.	The entire process stretches from the foetal stage until puberty, with the final step completing only at fertilisation.
9. Onset of Process	Starts at puberty and continues throughout the male’s reproductive life.	Starts before birth, with no new oogonia formed after birth.
10. End Products	Four haploid sperm cells (spermatozoa) from each primary spermatocyte.	One functional ovum and up to three polar bodies (which eventually degenerate) from each primary oocyte.

Difference between Spermatogenesis and Spermiogenesis

A common point of confusion is the difference between spermatogenesis and spermiogenesis:

Spermatogenesis: Refers to the entire sequence of events by which spermatogonia transform into mature spermatozoa (sperm). This includes mitosis, meiosis, and the final transformation of spermatids into sperm.
Spermiogenesis: This is the final part of spermatogenesis, where spermatids undergo morphological changes (formation of the tail, acrosome, and condensation of the nucleus) to become fully motile spermatozoa.

In simpler terms, spermiogenesis is a sub-step within spermatogenesis, focusing solely on the structural and functional maturation of spermatids.

Short Quiz (With Answers)

Try this quick quiz to test your understanding:

Which cells in the testis undergo mitosis to form primary spermatocytes?

A. Spermatogonia
B. Secondary spermatocytes
C. Spermatids
D. Sertoli cells
Answer: A. Spermatogonia

At which stage is the primary oocyte arrested in a female foetus?

A. Metaphase II
B. Prophase I
C. Telophase I
D. Prophase II
Answer: B. Prophase I

How many functional ova are typically produced from one primary oocyte?

A. Four
B. Three
C. One
D. Two
Answer: C. One

FAQs on Difference Between Spermatogenesis and Oogenesis

1. Why does oogenesis produce only one ovum while spermatogenesis produces four sperm?

Oogenesis involves unequal cytokinesis. Most of the cytoplasm goes to one daughter cell, forming a single large ovum, while the other cells become polar bodies. In spermatogenesis, cytokinesis is equal, resulting in four similar sperm cells.

2. When does spermatogenesis start in males?

Spermatogenesis typically begins at puberty (around the early teenage years) and continues throughout a male’s reproductive lifespan.

3. Can the process of oogenesis restart after menopause?

No. After menopause, females no longer produce mature ova as the follicles and primary oocytes in the ovaries have been depleted or become non-functional.

4. What is the importance of polar bodies in oogenesis?

Polar bodies help discard the extra sets of chromosomes and concentrate the cytoplasm into one large ovum, ensuring it has enough resources for early embryonic development if fertilisation occurs.

5. Which hormones regulate spermatogenesis and oogenesis?

Spermatogenesis is primarily regulated by Follicle Stimulating Hormone (FSH) and Luteinising Hormone (LH), along with testosterone.
Oogenesis is mainly controlled by FSH and LH, along with oestrogen and progesterone.