When Melanie Boivin learned that her young daughter Flavie had a rare condition which would damage her fertility, she was determined to find a way to help her.
After a year of research on the Internet, talking to experts and discussing it with her partner, she came up with the answer - to donate some of her own eggs for eventual use by seven-year-old Flavie.
"I told myself if she had needed another organ like a kidney I would volunteer without any hesitation, and it is the same kind of thought process for this.
Now 21 of Miss Boivin's eggs have been put into deep freeze, the first time such a mother-daughter donation has been made.
Miss Boivin, a French-Canadian, lives with partner Martin Cote, 35, a financial analyst, and their three children in Montreal.
Flavie was born with Turner Syndrome, a chromosomal disorder that affects one in every 2,000 girls born. It causes infertility and means Flavie will probably never be able to have a baby without donated eggs, but a major worry for her mother was the worldwide shortage of such eggs.
Miss Boivin said: "For a complete year I was thinking about it and did some research on the Internet and was discussing it with my partner because we were concerned about the ethical questions - would I look at the child as my grandchild or as my own?
"We were also concerned about the financial impact, the physical impact on me and the emotional impact on the family. After a year I was convinced there were more advantages than disadvantages."
She contacted the McGill reproductive centre in Montreal which has a major egg freezing programme designed to help cancer victims. After an in-depth interview with the ethics committee, she was accepted for treatment.
Professor Seang Lin Tang, medical director of the centre, said mother-to-daughter egg donation had never before been attempted.
He said: "Because there is a tremendous shortage of egg donors worldwide - we have 300 couples waiting here - couples often search for a donor among family members and this is generally ethically acceptable.
"Intergenerational egg donation has been problematic because it usually involves a daughter donating to her mother, which raises the possibility of coercion and feelings of obligation.
There is no time limit on the eggs being stored in Canada, though in the UK it is unlawful to store eggs which are not for a woman's own use for more than ten years.
Genetic diagnosis could be applied to the eggs before fertilisation to ensure there was no risk of Turner Syndrome being passed on.
Miss Boivin, who has an 11-year-old son Jamie and a healthy second daughter Clara, two, said: "Flavie is full of life. She is always happy and smiling and she is a very social child. She is brilliant at school.
"I do not want to oblige her to use the eggs. I want to give her the option."
Details of the donation were released yesterday at the European Society of Human Reproduction and Embryology in Lyon, France.
Josephine Quintavalle, of Comment on Reproductive Ethics, said: "This is very worrying. We have to stop thinking of women only in terms of their reproductive potential. The daughter could live a full and happy life without having children of her own."
But Dr Richard Kennedy of the British Fertility Society, which represents specialists working in the field, said: "Here is a mother who has the capacity to do something to help her daughter have a child. This altruistic behaviour is not dissimilar to the scenario where a parent donates a kidney to a child."