Women with typical genetic development are usually capable of giving birth from puberty until menopause.
In Old English, wīfmann meant "female human", whereas wēr meant "male human".
A fetus usually develops into a male if it is exposed to a significant amount of testosterone (typically because the fetus has a Y chromosome from the father).
It is a popular misconception that the term "woman" is etymologically connected to "womb".
"Womb" is actually from the Old English word wambe meaning "stomach" (modern German retains the colloquial term "Wampe" from Middle High German for "potbelly").
Later at puberty, estrogen feminizes a young woman, giving her adult sexual characteristics.
An imbalance of maternal hormonal levels and some chemicals (or drugs) may alter the secondary sexual characteristics of fetuses.
Most women have the karyotype 46, XX, but around one in a thousand will be 47, XXX, and one in 2500 will be 45, X.
This contrasts with the typical male karotype of 46, XY; thus, the X and Y chromosomes are known as female and male, respectively.
In particular, previously common terms such as office girl are no longer widely used.
Conversely, in certain cultures which link family honor with female virginity, the word girl is still used to refer to a never-married woman; in this sense it is used in a fashion roughly analogous to the obsolete English maid or maiden.
The term woman is usually reserved for an adult, with the term girl being the usual term for a female child or adolescent.
The term woman is also sometimes used to identify a female human, regardless of age, as in phrases such as "women's rights".
Because humans inherit mitochondrial DNA only from the mother's ovum, genetic studies of the female line tend to focus on mitochondrial DNA.