The board of referees allowed Christian Martin to claim 35 weeks of benefits to care for one of his baby daughters after a separate claim to care for her twin had already been made by his wife, Paula Critchley. (CBC)

The Canada Employment Insurance Commission is challenging a decision to let both parents of twin baby girls claim parental benefits.

Christian Martin, the Ottawa father involved in the case, learned Thursday that the commission is appealing a ruling by its board of referees in September, said a news release from Multiple Births Canada, a group that represents families with multiple births.

Martin's wife Paula Critchley gave birth to identical twins Lucie and Athena in April.

The board agreed to allow Martin to claim 35 weeks of benefits to care for one of his baby daughters after a separate claim to care for her twin had already been made by Critchley.

Normally, under Canadian law, the parents may take a total of 35 weeks of parental leave following a birth or adoption while receiving benefits under Canada's Employment Insurance program, no matter how many children are born to or adopted by the parents at the same time.

The weeks taken by each parent are added together, so if both parents take the leave at the same time, they only get paid parental leave for 17.5 weeks (although the birth mother may also take 15 weeks of maternity leave).

Martin and Critchley both applied for parental benefits after learning Critchley was pregnant with twins. Martin's claim was initially turned down, but he appealed to the board, which later ruled in his favour.