The primary oocytes are arrested at which stage of meiosis before birth?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → Prophase I
Option (1) Metaphase I — Incorrect. The oocyte does not get this far before birth; it stops earlier, in prophase I.
Option (2) Prophase II — Incorrect. Prophase II belongs to the second meiotic division, which is completed only at fertilisation.
Option (3) Prophase I — Correct. In the fetal ovary the oogonia enter prophase I and are temporarily arrested there; these cells are the primary oocytes.
Option (4) Anaphase I — Incorrect. Anaphase I comes only when the first division resumes, in the tertiary follicle after puberty.
NCERT Extract:
Gametogenesis – “… The process of formation of a mature female gamete is called oogenesis which is markedly different from spermatogenesis. Oogenesis is initiated during the embryonic development stage when a couple of million gamete mother cells (oogonia) are formed within each fetal ovary; no more oogonia are formed and added after birth. These cells start division and enter into prophase-I of the meiotic division and get temporarily arrested at that stage, called primary oocytes.”