Surgical Transition is where Sexual Reassignment Surgery is performed, which is the process of using surgical means to replace or suppliment the primary sexual characteristics of the patient with ones that align with their preferences. It is worth noting here that not all trans individuals will want (or be able to afford) such extensive procedures for various highly personal reasons.
Top surgery is a term used for any type of gender affirming surgical procedure that is done to the chest area of an individual, most often a mastectomy in order to reduce breast sizes (and shape) to align with that of cis men.
Bottom surgery is a term used for any type of gender affirming surgical procedure that is meant to augment, modify, or replace the genitals of an individual. This is often accompanied by a gonadectomy and/or hysterectomy, such as replacing a MTF (male to female) patient's testicals and penis with a vagina and rarely (infertile) womb. Such treatments have a wide varity of nuanced choices for the patient, and many are being experimentally researched as the care is becoming more medically accepted. For example, transplanting a womb to a trans individual (possibly sourced by another trans individual seeking a hysterectomy) is a form of surgery that has been considered recently but never successfully been performed, and has likely not been attempted for nearly 100 years. This is likely because in recent years cis women have successfully had such transplants performed, thus setting precedent.
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