What is one difference between oogenesis and spermatogenesis?

One distinct difference between oogenesis and spermatogenesis is that spermatogenesis starts after puberty while oogenesis starts during fetal life.

In humans, the female already possesses all of the oocytes that she will make in the whole of her life even before she is born. Before a baby girl is born, she has approximately 7 million oogonia majority of which die just two months prior to her birth. The remaining oogonia go on to become primary oocytes after entering meiosis I.

Spermatogenesis on the other hand is initiated in the male testis with onset of puberty.