Jacob Zuma married his third wife in early January
South Africa's governing African National Congress has defended President Jacob Zuma over claims that he fathered a child outside marriage.
The ANC said Mr Zuma had broken no laws and that there was "nothing shameful" in a relationship between two people.
Opposition parties and newspapers have accused Mr Zuma, who has three wives, of setting a bad example in a country battling an epidemic of HIV and Aids.
One member of parliament urged him to seek treatment for "sex addiction".
Kenneth Meshoe said Mr Zuma should get help like "Tiger Woods did".
South Africa's Sunday Times newspaper reported that the president, who is engaged to a fourth woman, had fathered a girl born on 8 October 2009 with Sonono Khoza, 39, the daughter of the 2010 World Cup Local Organising Committee boss Irvin Khoza.
Mr Zuma, 67, was said to have paid compensation for the pregnancy, suggesting that he was not denying paternity.
In several South African cultures, the father of a child born out of wedlock pays damages known as Inhlawulo to the family of the baby's mother.
Mr Zuma has so far not commented but Ms Khoza has denied having had a baby last year, reports the Sowetan newspaper.
On Monday an ANC spokesman issued a statement tacitly confirming the president had fathered a child and asserting that it considered the matter private.
"We are of the view that the media and some political commentators are making a mountain out of nothing," Jackson Mthembu said.
"Why should a relationship between two adults be made an issue? Why should it make headlines? Why is it characterised by some media as a 'Shame to the nation'?" he asked, referring to the headline of an editorial in the Sowetan.
Mr Mthembu said the criticism of the president was "disingenuous".
"There is nothing wrong that the president has done. There is nothing 'shameful' when two adults have a relationship," he said.
"By being involved with any other person, President Zuma is not guilty of any offence and he has not breached our constitution or any of our laws," he added.
The spokesman also said the ANC saw no links between its policies on HIV/Aids and Mr Zuma's personal life.
'Sending a message'
South Africa has the highest number of HIV infections in the world - more than 5 million people.
MRS JACOB ZUMA
Thobeka Madiba-Zuma - married, January 2010 (above)
Nompumelelo Ntuli - married, January 2008
Sizakele Khumalo - married, 1973
Home Affairs Minister Nkosazana Dlamini-Zuma - divorced, 1998
Kate Mantsho Zuma - died, 2000
Mr Zuma was praised last year when he announced major changes to the country's Aids policy, which included increasing the roll-out of anti-retroviral drugs.
But opposition parties now say his behaviour contradicts the government's stance on HIV prevention - for example preaching regular condom use and faithfulness.
"He is the one who is always preaching responsible sexual behaviour, but it seems he is sending a message which says 'Don't do as I do, do as I say'," Independent Democrats leader Patricia de Lille said.
This is not the first time that the president's sexual life has been under the spotlight.
In 2006, while being acquitted of rape, Mr Zuma admitted that he had made a mistake by having unprotected sex with a woman he knew to be HIV-positive. She was also the daughter of a family friend.
Mr Zuma has been married five times in all, most recently in January, and is also engaged to another woman. He has 19 children according to his office, but it is not clear if that includes the baby born last October.