Question: 173: At which stage of the life the oogenesis process is initiated?
(1) Birth
(2) Adult
(3) Puberty
(4) Embryonic development stage
Answer: Option (4)
Explanation:
Oogenesis is the process of formation of female gametes called ova.
In human females, oogenesis begins during the embryonic development stage.
During fetal life, primordial germ cells differentiate into oogonia, which multiply by mitosis.
These oogonia enter meiosis I and get arrested at the prophase I stage, forming primary oocytes.
Thus, the initiation of oogenesis occurs before birth, during embryonic development.
At puberty, these primary oocytes resume further development,
but the process itself has already been initiated earlier.