Genital nullification can mean many different kinds of surgeries to take away most or all of a person's reproductive organs and genitals. Some nonbinary people seek this as part of their physical transition in order to be sexless, and/or in response to gender dysphoria that makes them feel alienated from having any kind of genitals. However, one need not have genital nullification in order to be genderless, because gender identity is different than physical sex. A person can be genderless while having genitals that most people would think of as female, male, or intersex. A person also need not identify as genderless in order to seek genital nullification.
A person's options for genital nullification depend on what kind of body they started out with. For people who had a penis and testicles, genital nullification can mean using surgery to take away those parts, called emasculation. For people who had a uterus, vagina, and labia, genital nullification can mean using surgery to take away some of those parts, called hysterectomy, vaginectomy, and some kinds of labiaplasty.