The process of oogenesis, which occurs in females, results in the production of one mature ovum (egg) and three other cells known as polar bodies. Here are the four cells produced by oogenesis:

1. Primary Oocyte: This is the starting cell of oogenesis and is formed during embryonic development. It undergoes the first meiotic division, resulting in the formation of two cells.

2. Secondary Oocyte: One of the cells produced from the first meiotic division is the secondary oocyte. It is larger and contains more cytoplasm compared to the other cell, which becomes the first polar body. The secondary oocyte undergoes a brief interphase before entering the second meiotic division.

3. Ovum (Mature Egg): The second meiotic division of the secondary oocyte leads to the formation of two cells: the mature ovum and the second polar body. The ovum is the largest of the cells produced during oogenesis and contains the majority of the cellular components necessary for fertilization and early embryonic development.

4. Polar Bodies: Polar bodies are small cells with little cytoplasm and lack the ability to fertilize. During oogenesis, three polar bodies are produced. The first polar body is formed during the first meiotic division, while the second and third polar bodies result from the second meiotic division. The polar bodies eventually disintegrate and play no role in reproduction.