The process is identical to spermatogenesis as far as karyokinesis is concerned, but differs in cytokinesis. At both Telophase I and II there is unequal division resulting in a large secondary oocyte and ootid, respectively. The smaller cell is called a polar body. The first polar body divides equally. The end result is one ootid converting into an ovum and three non-functional polar bodies which degenerate.
Spermatogenesis produces numerous small gametes and oogenesis produces one large gamete.
The timing of oogenesis is different in that female gamete production starts in utero and starts and stops all through her reproductive lifetime. Spermatogenesis does not begin until the male reaches puberty, but then is continuous until the end of his reproductive lifetime. One consequence of this difference is the increased risk of chromosomal birth defects in infants born to women over the age of 35, due to defective chromosomal separation during anaphase. I in both sexes as a result of intertwining DNA strands prior to DNA replication. This crossing over results in DNA strands being broken and rejoining to another strand.