Reed, et al (GIRES) (2009) an estimated 6,500 of the 10,000 Reed, et al (GIRES) (2009) Prevalence, incidence, growth and geographic distribution Reed, et al (GIRES) (2009) Gender Variance study an estimated 6,500 of the 10,000 different kinds of surgery Reed, et al (GIRES) (2009) an estimated 60,000-90,000 many different kinds of surgery involved Reed, et al (GIRES) (2009) Reed, et al (GIRES) (2009) small in number different kinds of surgery small in number study small in number