Two South African toddlers accidentally swapped at birth should stay with the families who raised them and not be returned to their biological parents, a court-appointed expert said Wednesday. The two children, a boy and a girl who are now aged four, were born on the same day in 2010 in a Johannesburg hospital but ended up being taken home and raised by the wrong parents after nurses mixed up their identities. The families were unaware of the mistake until one of the mothers underwent tests when her ex-husband refused to pay child support. One of the mothers had initially wanted to get her biological child back, while the other preferred to keep the one she had raised, leaving the North Gauteng High Court to decide.