A Kingston, Ont., man is set to donate part of his liver to save one of his twin girls, but cannot donate to both.

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Twins Binh, left, and Phuoc Wagner have Alagille syndrome, which affects the function of their livers. Their father, Michael, is set to donate part of his liver to save one girl, but cannot donate to both. (Wagner family/Canadian Press)

Michael and Johanne Wagner's three-year-old girls Binh and Phuoc have Alagille syndrome, which affects the function of their livers. The couple adopted the Vietnamese twins when they were 18 months old. They have seven other children.

Doctors say both need transplants to survive, but the girls' mother said their father is the only match that has been found so far.

Johanne Wagner said surgeons at Toronto General Hospital are set to operate on Michael and one daughter in about two weeks.

They cannot bear to choose, so doctors will decide based on the best candidate.

The Wagners are still hoping to find a donor for their other daughter, who will die if she doesn't get a new liver. The couple has a Facebook page and a blog called One More Potato in the Pot with more information about the twins.

Donors must be between 18 and 55 years old with A or O blood type. Volunteer donors are asked to contact the University Health Network in Toronto.