In species which produce two morphologically distinct types of gametes, and in which each individual produces only one type, a female is any individual which produces the larger type of gamete—called an ovum (or egg)—and a male produces the smaller type—called a spermatozoon (or sperm cell).
Gametogenesis is the development of diploid germ cells into haploid eggs or sperm, (respectively oogenesis and spermatogenesis). It is different for each species but the general stages are similar. The development of eggs (oogenesis} and sperm (spermatogenesis) have many features in common. They both involve:
- Extensive morphological cell differentiation
- Unable to survive for very long if fertilization does not occur
They also have major differences, especially
- Different timing of maturation: oogenic meiosis is interrupted at one or more stages (for a long time) while spermatogenic meiosis is rapid and uninterrupted.