The beginning.

'It's temporary. I'll come back for them.''
The sympathetic lady looked at the young woman, eyebrows raised.
'The baby's father. He doesn't want the boy.''
Therefore the two children were left in the hospice. Social workers looked for a family to take both brother and sister, but they were so different, one black, one white, that families and misplaced bigotry didn't want such a mismatch. Eventually, two families were found in some remote part of the country.
The mother never came back.
The temporary situation became permanent, no one realising that they had abandoned two innocents to a dire fate.