"Through DNA testing, Ghanaian Isaac Owusu discovered that only one of his four sons was actually his. After the death of his wife 14 years ago, Owusu left his four children in the care of his family in Ghana while he travelled to the United States to carve out a new life. Eventually Owusu was granted US citizenship, but when he applied to bring his sons to join him he took a DNA test to prove that the boys were genetically related to him and, shockingly, the results showed that they were not. Three of the four boys had, according to the test, been fathered by someone else. Owusu was distraught and his three younger sons simply did not understand why they could not join him. Owusu tells Outlook presenter Heather Payton how he is still trying to reunite his family, and Michele Garnett McKenzie, a lawyer specialising in immigration cases talks about how common the situation is."

Rebroadcast is available for a limited time at http://www.bbc.co.uk/worldservice/programmes/outlook.shtml#Fri.