A bill to amend the Birth and Death Registration Act to allow people to change their sex as entered in the register was approved in the national assembly on Friday.
The African Christian Democratic Party was the only party to object to the Alteration of Sex Description and Sex Status Bill.
The ACDP's Steve Swart said the bill provided for the alteration of the description of people in the national population register whose sex organs had been altered by surgical or medical treatment or "by evolvement through natural development resulting in a sex change".
The ACDP believed a person's sex for legal purposes was a wholly biological question and "is fixed at birth".
Surgical or medical intervention did not change ones sex, he said.