Sex change

Sex change is gender reassignment therapy, that is, all medical procedures transgender people can have, or specifically to sexual reassignment surgery, which usually refers to genitalia surgery only. It is also sometimes used for the medical procedures intersexual people undergo, or, more often, are subjected to as children.
"Sex change" is sometimes also used for the whole process of changing gender role and the medical procedures associated with it. Since changing of gender role, i.e. living as a woman instead of living as a man, or living as a man instead of living as a woman, is much more important to almost all transgender people than any medical procedures, this use is even more inaccurate. (Of course, medically induced changes and surgeries are often needed to make a change of gender role at all possible, both socially and legally. Also, they can have a very significant impact on the well-being of people having them.)

Main article: Sex reassignment therapy
See also: Transsexualism and Sex reassignment surgery
Sex change is a term often used for sex change in humans, that is all medical procedures transgender people may pursue, or specifically to sex reassignment surgery, which usually refers to genital surgery only. It is also sometimes used for the medical procedures intersex people undergo, or, more often, are subjected to as children. "Sex change" is sometimes also used for the whole process of changing gender role and the medical procedures associated with it. Since changing of gender role, i.e. living as a woman instead of living as a man, or living as a man instead of living as a woman, is much more important to almost all transgender people than any medical procedures, this use is even more inaccurate. (Of course, medically induced changes and surgeries are often needed to make a change of gender role at all possible, both socially and legally. Also, they can have a very significant impact on the well-being of people having them.)
Many people also see "sex change" as factually inaccurate. Sex in humans is usually determined by four factors:
Chromosomes
Gonads (Ovaries and/or testicles)
Hormone status
Primary sex characteristics, sometimes also secondary sex characteristics

Not all of these factors can be changed, however:
Chromosomes cannot be changed.
Gonads can be removed, but not replaced
Hormone status is easily changed
Existing secondary sex characteristics can to some extent be changed; existing ones mostly through surgery, non-existing ones can be induced to grow through hormones.
For example: Changing a male genital anatomy into a good or even excellent female appearance with functioning is complicated, but entirely possible; changing a female genital anatomy into an even reasonably male appearing one however is extremely complicated and not successful very often; function is always limited.


Gender reassignment is usually preceded by a period of feminization or masculinization. This is accomplished by the use of either synthetic/natural hormones (such as estrogens, androgens, progestogens and antiandrogens). The most common period before gender reassignment surgery is two years, as specified by the Standards of Care for the Health of Transsexual, Transgender, and Gender Nonconforming People. Body changing hormones are normally started after sufficient counselling, or a period of living 'full-time' (in the target gender) for a minimum of six months. Transgenders from all over the world become medical tourist and fly to other countries to have their surgeries because they simply can't afford it back home. They save over 70% by travelling to Mexico, Thailand, India and Serbia.

Natural sex change in humans
Several medical conditions can result in a natural sex change in humans, where the appearance at birth is somewhat, mostly, or completely of one sex, but changes over the course of a lifetime to being somewhat, mostly or completely of the other sex. The overwhelming majority of natural sex changes are from a female appearance at birth to a male appearance after puberty, due to either 5-alpha-reductase deficiency (5alpha-RD-2) or 17-beta-hydroxysteroid dehydrogenase deficiency (17beta-HSD-3).A relative handful of male to female changes have been reported, and the etiologies of these are not well understood.
Genetic females (with two X chromosomes) with congenital adrenal hyperplasia lack an enzyme needed by the adrenal gland to make the hormones cortisol and aldosterone. Without these hormones, the body produces more androgen, a type of male sex hormone. This causes male characteristics to appear early (or inappropriately).
Genetic males (with one X and one Y chromosome) with androgen insensitivity syndrome is resistant to male hormone androgen. As a result, the person has some or all of the physical characteristics of a woman, despite having the genetic makeup of a man. The degree of sexual ambiguity varies widely in persons with incomplete AIS. Incomplete AIS can include other disorders such as Reifenstein syndrome which is associated with breast development in men.