Unlike a father, who has the right to go out to work and pursue a career, a mother has the right to stay at home to care for the children or to go out to work and pursue a career.
Until sex equality laws insist that a the father and mother of a child each have equal responsibility for the care and financial support of their children then situations like this will persist. The law currently regards women as breeding machines who are in most circumstances best supported by the male of the species.
There was a bit in todays paper that said the couple had split up. Perhaps the mother was trying to claim benefits, and as far as i know the CSA will come after the father for maintainence once the mother has named the man who "fathered" the child. To my mind this does seem harsh on the doner as he stated he didn't want any involvement with the child or the mother and her partner at the time of the donation. Some people cannot be trusted to keep their side of an agreement, especially when money is at stake.