A woman is a female human being. The word woman is usually reserved for an adult, with girl being the usual term for a female child or adolescent. The plural women is also sometimes used for female humans, regardless of age, as in phrases such as "women's rights". Women with typical genetic development are usually capable of giving birth from puberty until menopause. There are also trans women (those who have a male sex assignment that does not align with their gender identity), and intersex women (those born with sexual characteristics that do not fit typical notions of male or female).
Womanhood is the period in a human female's life after she has passed through childhood and adolescence, generally around age 18.
The word woman can be used generally, to mean any female human, or specifically, to mean an adult female human as contrasted with girl. The word girl originally meant "young person of either sex" in English; it was only around the beginning of the 16th century that it came to mean specifically a female child. The term girl is sometimes used colloquially to refer to a young or unmarried woman; however, during the early 1970s, feminists challenged such use because the use of the word to refer to a fully grown woman may cause offence. 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 (or its equivalent in other languages) is still used to refer to a never-married woman; in this sense it is used in a fashion roughly analogous to the more-or-less obsolete English maid or maiden.
Whether or not a child is considered female does not always determine whether or not the child later will identify themselves that way (see gender identity). For instance, intersex individuals, who have mixed physical and/or genetic features, may use other criteria in making a clear determination. At birth, babies may be assigned a gender based on their genitalia. In some cases, even if a child had XX chromosomes, if they were born with a penis, they were raised as a male. There are also trans women who were assigned as male at birth, but identify as women; there are varying social, legal, and individual definitions with regard to these issues.
Women's health refers to health issues specific to human female anatomy. There are some diseases that primarily affect women, such as lupus. Also, there are some sex-related illnesses that are found more frequently or exclusively in women, e.g., breast cancer, cervical cancer, or ovarian cancer. Women and men may have different symptoms of an illness and may also respond to medical treatment differently. This area of medical research is studied by gender-based medicine.