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.
"We also have an objection to the inclusion of the phrase 'evolvement through natural development resulting in a sex change', as we reject the unscientific basis of Darwinism and the evolution theory, and fail to see the need for the inclusion of this phrase when no evidence exists of such occurrences in South Africa.
"This is another example of the impact of secular humanism on our legislative process - secular humanism being undergirded by concepts of atheism and evolution," Swart said.
Richard Pillay of the New National Party supported the bill, saying South Africa was a state in transition and everyone knew "some conveniently choose to ignore that fact".
Such people further tried to resist all forms of change, and that resistance was based on their own inherent and selfish prejudice, and usually financial interests.
"It is a common occurrence to find that those that resist change cloak their selfish interests in a religious guise and appoint themselves as God's representatives here on earth," he said.
The bill sought to bring about a fundamental change in the lives of certain people.
"Could there be any moral, ethical or spiritual reasons for not supporting this bill?
"We believe that it is an individual matter and those that seek to use this piece of legislation should be able to exercise their constitutional rights and do so without being dictated to by any other person or organisation," Pillay said.
The bill was adopted with only the ACDP and National Action objecting, and will now go to the national council of provinces for concurrence. - Sapa