Both genetics and environment shape the prenatal development of a female.
The ova are defined as the larger gametes in a heterogamous reproduction system, while the smaller, usually motile gamete, the spermatozoon, is produced by the male.
Mammalian females bear live young (with the rare exception of monotremes, which lay eggs).
Some non-mammalian species, such as guppies, have analogous reproductive structures; and some other non-mammals, such as sharks, whose eggs hatch inside their bodies, also have the appearance of bearing live young.
These abbreviations were contracted into the modern symbols.
Although most species with male and female sexes have individuals that are either male or female, hermaphroditic animals have both male and female reproductive organs.Intersex conditions can also give rise to other combinations, such as XO or XXX in mammals, which are still considered as female so long as they do not contain a Y chromosome, except for specific cases of testosterone deficiency/insensitivity in XY individuals while in the womb.However, these conditions frequently result in sterility.Mammary glands are present in all mammals, although they are seldom used by the males of the species.Most mammalian females have two copies of the X chromosome as opposed to the male which carries only one X and one smaller Y chromosome (but some mammals, such as the platypus, have different combinations).