Kevin Barber says benefit rules discriminate against dads and treat him as if he was an 'absentee' father even though he looks after his youngest son for half of the time.
His lawyers argue the benefits regime violates his right to respect for his home and private life and amounts to unlawful discrimination under Article 14 of the European Convention on Human Rights.
Mr Barber had his judicial review challenge dismissed by a judge in July, but today he was granted leave to take his case to the Court of Appeal.
Lord Justice Carnwath, sitting with Lord Justice Ward, observed that the case raised issues of 'some general importance' and took less than five minutes before declaring his complaints 'arguable' and that his appeal had 'a reasonable prospect of success'.
Richard Drabble QC, for Mr Barber, told the judges the case raised issues of 'fundamental importance' about the extent of the Human Rights Convention ban on discrimination.
The 'all or nothing' approach to Child Benefit meant many child carers, particularly fathers, were being severely disadvantaged.
'This is not being faced up to by the Government and it raises real social policy issues', he told the court.
Mr Barber, a leading firefighter with the Derbyshire brigade, argues that the Child Benefit system was unlawfully 'skewed' in favour of his ex-wife.
He divorced his wife from Nottingham in 1998, after 10 years marriage. Their eldest child lives with him and his new wife.
But, under a court-approved arrangement, Mr Barber and his ex share the care of the younger boy who spends half of each week with his mother and the other half with his father.
Mr Barber thought it was unfair that his former wife should receive all the child benefit paid in respect of the younger son.
But his request to the Secretary of State for Work and Pensions to split the benefit equally between himself and the younger boy's mother was refused in August last year.
Mr Drabble said the Child Benefit regulations deemed fathers in Mr Barber's position as being 'absentee' parents.
Child Benefit, he said, is a 'gateway benefit', and the fact that Mr Barber cannot claim a penny in respect of the younger boy means he is also denied a whole range of other state assistance.
In granting leave to appeal, Lord Justice Ward said if Mr Barber in the end won his case, the 'all or nothing' Child Benefit rule might be declared 'incompatible' with the Human Rights Act.
No date was set for the full hearing of the appeal which will take place before three senior Lords Justice of Appeal, possibly including the Master of the Rolls, Lord Phillips.
STRAND NEWS SERVICE