Gender transition is the process of changing one's gender presentation or sex characteristics to accord with one's internal sense of gender identity – the idea of what it means to be a man or a woman, or to be non-binary or genderqueer. For transgender and transsexual people, this process commonly involves reassignment therapy (which may include hormone replacement therapy and sex reassignment surgery), with their gender identity being opposite that of their birth-assigned sex and gender. Transitioning might involve medical treatment, but it does not always involve it. Cross-dressers, drag queens, and drag kings tend not to transition, since their variant gender presentations are (usually) only adopted temporarily. Transition begins with a decision to transition, prompted by the feeling that one's gender identity does not match the sex that one was assigned at birth. One of the most common parts of transitioning is coming out for the first time. Transitioning is a process that can take anywhere between several months and several years. Some people, especially non-binary or genderqueer people, may spend their whole life transitioning and may redefine and re-interpret their gender as time passes. Transitioning generally begins where the person feels comfortable: for some, this begins with their family with whom they are intimate and reaches to friends later or may begin with friends first and family later. Sometimes transitioning is at different stages between different spheres of life. For example, someone may transition far with family and friends before even coming out at their workplace. Gender transition is sometimes conflated with sex reassignment surgery (SRS), but that is only one possible element of transition. Many people who transition choose not to have SRS, or do not have the means to do so. Whereas SRS is a surgical procedure, transitioning is more holistic and usually includes physical, psychological, social, and emotional changes. Some transgender and non-binary people have little or no desire to undergo surgery to change their body but will transition in other ways.