A woman who learned as a teenager that she would need fertility treatment to have a child yesterday spoke out for more donors to come forward and give other childless couples the opportunity of the "gift of life".

Marie Macrae, 32, from Inverness discovered when she was 19 that she would require IVF to have a family.

Seven years ago both she and husband Angus started the process which, after three attempts, led to her pregnancy. "Sophie has made our lives complete," she said. "It's the gift of life."

The couple made their plea following reports that the loss of anonymity for sperm and egg donors has led to a national shortage.

Since the law was changed two years ago to give children over 18 the right to know the identity of the donor responsible for their birth, the number of volunteers has plummeted.

At the Aberdeen Fertility Clinic, which provides the service for Grampian, the Highlands, the Western Isles and Orkney and Shetland, more than 40 couples are currently awaiting for up to two years for treatment.

Dr Mark Hamilton, lead consultant, said the number of egg donors had fallen from 17 in 2000 to just nine in 2006, while the number of sperm donors had fallen to just two in 2005 though it rose again to seven last year after a publicity campaign.

"Fertility is something most of us take for granted, but for approximately 500 couples a year in Grampian, having a child is difficult or impossible without help because of male or female infertility," he said.

Donors are not told the identity of the people receiving treatment using their eggs or sperm, but they can find out how many children have been born as a result of their donations. They do not have legal right of access to, or parental or financial responsibility for, any children born as a result of their donations.