The penis contains a long tube called the urethra which is responsible for carry sperm from the male to be place in the female's vagina.
The production of sperm cells is known as spermatogenesis . This process occurs continuously and takes place within the male testes. Hundreds of millions of sperm must be released in order for fertilization to take place. Oogenesis (ovum development) occurs in the female ovaries. In meiosis I of oogenesis, daughter cells are divided asymmetrically. This asymmetrical cytokinesis results in one large egg cell (oocyte) and smaller cells called polar bodies. The polar bodies degrade and are not fertilized. After meiosis I is complete, the egg cell is called a secondary oocyte. The haploid secondary oocyte will only complete the second meiotic stage if it encounters a sperm cell and fertilization begins. Once fertilization is initiated, the secondary oocyte completes meiosis II and is then called an ovum. The ovum fuses with the sperm cell, and fertilization is complete. The fertilized ovum is called a zygote.