Gender change operation also known as the sex change (SRS initialized as, also known as reconstructive surgery of the genitals, the sex affirmation surgery or sex reassignment surgery) is a term for surgical procedures by where the physical appearance of a person and the function of their existing sexual characteristics are altered to resemble that of the other sex. It is part of a treatment for gender identity Disorders of gender dysphoria transsexuals and transgendered people. It may also be performed on intersex people, often in childhood. Other terms for gender change operation include gender reassignment surgery, surgical reconstruction of gender, surgical reconstruction of the genitalia, surgical confirmation between the sexes, and most clinical conditions, such as the feminization orcidectomy genitoplasty or Penectomy, and vaginoplasty are used medically for trans women, with masculinizing genitoplasty often also used for trans men.

The best known of these surgeries are those that transform the genitals, which are also known as genital reassignment surgery or reconstructive surgery of the genitals (GRS). However, the meaning of "surgical sex change" has been clarified by organizing medical subspecialty, the World Professional Association for Transgender Health , to include while a large number of surgical procedures performed in medical treatment for "gender dysphoria". Medically necessary surgical sex reassignment include "total hysterectomy, bilateral mastectomy, reconstruction or augmentation breast including breast implants, if necessary, reconstruction of genitalia (by different techniques, which must be tailored to each patient and certain plastic reconstruction of the face. In addition, other non surgical procedures are considered medically necessary by wpath treatments, including electrolysis of the face.

The range of medically necessary surgery is different for trans women (male to female) rather than trans men (female and male). For women, trans, reconstruction of genitalia in general implies Surgical construction of a vagina, whereas in the case of trans men, genital reconstruction in May concern is the construction of a penis or metoidioplasty construction of a penis. In both cases for women and men trans trans, genital surgery may also involve procedures medically necessary for other accessories, such as orchiectomy or Vaginectomy.