New mum Madeleshia Hiscock was delighted when she gave birth to a beautiful baby boy.
But a month later, doctors told her that 'he' was actually a she.
Baby Kenny appeared to have male genitals at birth.
Madeleshia, 29, and her husband Kenneth, 30, went out and bought blue baby clothes and boys' toys with their daughter Zadeleshia, three, and told family and friends about their new son. But a few weeks after he was born, his parents felt something wasn't right.
They took him back to a hospital near their home in Vereeniging, South Africa, and after several tests, doctors revealed Kenny was a girl.
Kenneth was diagnosed with a rare genetic condition called congenital adrenal hyperplasia, an enzyme deficiency which causes abnormal male hormone production. This caused enlarged genitals, which at first had appeared to be male.
Madeleshia said: 'We were just stunned, in utter shock. I had no idea what to say - it seemed so unreal. It just didn't make any sense.
'When I'd had my first scan they thought Kenny was a girl but then when I had my second scan they said it was a boy.
'It felt like our baby's sex was changing every other minute - but I didn't expect there to be a problem after the birth.
'Even when he was born the doctors said Kenny was a boy. We had been buying blue baby grows and toy cars for weeks.
'Our first child Zadeleshia was a girl so we were really excited to be having a boy and had got everything ready.
'Now we had to tell everyone that we got our baby's sex wrong and buy different toys and clothes - I just couldn't take it in at first.'
There is no cure for CAH, which occurs in one in every 15,000 people, but it can be treated with daily cortisol tablets.
The couple have now renamed Kenny as McKenzi. Mum Madeleshia said: 'The doctor told us McKenzi is not really male or female, but somewhere between.
'But we have a beautiful daughter, and we're both incredibly proud.'
12-year old boy starts secondary school... as a girl
The Nub theory: how to predict your baby's sex at 12 weeks