Jessica Allen gave birth to two boys as a surrogate, but one was her biological child.
Jessica Allen was acting as surrogate when she thought she gave birth to 'identical twin' boys.
She later found out that one of the infants was in fact her biological son.
He was conceived when Jessica was already pregnant with the surrogate embryo, a rare occurrence known as superfetation.
Watch the Victoria Derbyshire programme on weekdays between 09:00 and 11:00 on BBC Two and the BBC News Channel.
14 Nov 2017