Why do women go through meiosis if they are born with all the eggs?

• A. Eggs must mature through puberty before they can be fertilized.
• B. Meiosis occurs only in males.
• C. Meiosis doubles the number of eggs.
• D. Meiosis occurs after fertilization.

Answer: (A)

Meiosis in female eggs is initiated early but held in a paused state until puberty. Although a girl is born with all the egg cells she will ever have, those cells begin meiosis during development and are arrested in an early stage. When puberty starts, hormonal changes trigger ovulation and the egg resumes and completes meiosis I right before it is released. It becomes a secondary oocyte, which then sits paused again at a later stage until fertilization. Only if a sperm fertilizes the egg does meiosis II finish, producing the mature egg. So, activation of meiosis and readiness for fertilization hinge on puberty, not on birth alone.