Although studies have suggested that the positive consequences of sex reassignment surgery outweigh the negative consequences, it has been suggested that most studies investigating the outcomes of sex reassignment surgery are flawed as they have only included a small percentage of sex reassignment surgery patients in their studies. These methodological limitations such as lack of double-blind randomized controls, small number of participants due to the rarity of transsexualism, high drop-out rates and low follow-up rates, which would indicate need for continued study.