Under a fatwa or religious decree by the Islamic republic's founder Ayatollah Ruhollah Khomeini, Iran recognises transsexuality.
Sex change operations are common, with part of the fees paid by the authorities.
"To better protect transsexuals, a draft bill on all aspects, judicial and religious, has been prepared and sent to parliament's research centre, which is examining it," said Farid Habibollah Masoudi, deputy head of the social affairs assistance department.
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"Since 2002, 1,800 people have applied to our service," he said, including 330 in the Iranian year that ended in March.
In Iran, once a person's transsexuality has been confirmed by psychiatrists, the person in question is referred to the justice and forensic science departments.
"To prevent any problems because of their appearance, they are given a letter confirming their transsexuality so the police do not take action against them," the official added.
Despite being very traditional, Iranian society accepts transsexuality. However, homosexuality is outlawed, with the death sentence handed down to reoffenders.