Their mother was a full sister to Amunhotep III, Akhenaten's father.  She was a woman of great beauty but of unstable mind and appetites.  Her name was Nofrure and she was the natural choice for a wife for Amunhopep III but her instability excluded her from that role.  Nevertheless she seduced her brother Amunhotep while he was married to Tiye and conceived the daughter who became known as Sitamun.

A hasty marriage was arranged with Anen, a brother of Tiye and Aye.  The child was however brought up by Yuya and Tuya, the parents of Tiye, Aye and Anen.  Before long Nefertiti was born to the Princess Nofrure.  Following her was the birth of Nofrure Ta Sherrit.  This was a shock as the baby was obviously of Nubian descent.  The Princess confessed that she could not remember which of the Nubian slaves she had dallied with and in fact it may have been more than one. She should have been executed for her crime but Amunhotep loved her and so she remained married to Anen to whom she bore another daughter, Mutnodjme, after which she died.

Of course Anen was given many privileges to quietly accept the disgrace of his wife. The child of a slave born to a Royal Princess would normally have been left exposed to die. This would have happened to Nofrure Ta Sherrit except that Amunhotep could see a political advantage for the future with this child. 

Many surrounding countries wanted Egyptian Royal Princesses in marriage to their Kings.  Egypt never gave its Princesses in foreign marriages but Amunhotep saw no reason why he could not have this child raised privately and given in a political marriage.  The foreign King would have no way of knowing that the child was fathered by a slave.  Thus Nofrure Ta Sherrit came to be raised with Sitamun by Yuya and Tuya.  When she was of marriageable age she was sent to Ashur the capital of Assyria and given in marriage to King Ashur the Great.  She was not his major wife but she became a favourite wife and a surrogate mother to the royal children whose mothers had died.

In due time Nofrure Ta Sherrit gave birth to Nadiamerrimemne who at the age of eight years was sent to the court of Akhenaten in Akhetaten to become the Royal Princess Ankhsenpaaten.