An engaged South African couple who dated for five years found out they are brother and sister after their families met.
The woman is due to give birth next month, is devastated by the discovery that the father of her child is her brother.
They met at university and had decided they wanted to introduce their single parent families to each other before they got married.
At the family meeting it emerged they were brother and sister who had been separated as small children.
The unnamed couple are still in shock after making the discovery last Saturday.
A local newspaper, the Sowetan reported that the siblings had been raised separately after their mother and father went through an acrimonious divorce.
The newspaper wrote: “Their parents separated when the woman was eight months old and the man was two years old.
“The man’s father said he dumped his wife in 1983 because she was cheating on him. The girl was raised by her mother, while her brother was raised by his father.
“Neither of them knew they had a sibling.”
The newspaper also reported that the children grew up separately with their single parents near the towns of Nelspruit and Bushbuckbridge, which lie 50 miles apart in South Africa’s eastern Mpumalanga province.
The couple reportedly met again at university in 2006 and fell in love.
Their families did not meet throughout their five-year relationship, until they were brought together last week to discuss wedding arrangements.
In many African cultures it is traditional for the family of a male partner to pay a lobola, or “bride price”, to that of his fiancée.
Traditionaly, the two families arrange a summit at which they are formally introduced and able to conduct the negotiations.
The couple’s plans were derailed when their parents came face to face and revealed their bombshell.
The woman told the Sowetan she was devastated by the revelation.
“It was love at first sight. We were studying together at Tshwane University of Technology in Nelspruit.
“When I first saw him, we connected. We fell in love and since that day, we never looked back.
“All we wanted to do was just to have a family and many kids.
“So you can imagine how shocked we were when they broke the news. We are going to have a child together. We do not know what we will tell him when he grows up.”
The couple decided to split after hearing the news and were discussing how to handle the shock with their separated parents.
The man said: “We can’t think straight at the moment and will just take everything one step at a time.”
Incest remains one of society’s last taboos and is an unthinkable concept to most people.