Daughter may give birth to mother's child?

I read a very interesting article this week titled "daughter may give birth to mother's child".
A girl aged seven has turner syndrome which makes her infertile when she matures. Out of motherly love, her thirty five year old Canadian mother had decided to freeze her eggs so that one day her daughter may become a mother herself.
This is the first time that a mother-to-daughter donation has been made, though there have been cases of sister donating to sister before. Donating eggs is nothing new, but there is a shortage of egg donors in Canada since legislation in 2004 prevented women from selling their eggs.
Some people are touched by the mother's act and agree with the donation. However, some strongly against this donation. Negativity has risen since this story was made public. The only negativity reaction had come from an ethics professor in Toronto who did not think that the interest of the unborn child had been taken into account. Experts who have spoken to the press have also expressed concern as to the psychological welfare of the yet unborn child.
I do not agree to such donation. I can feel the Canadian mother's love and concern towards her daughter but I am against to such donation.
If the daughter dives birth to a child using her mother's eggs, such a baby would be the sibling of the birth mother at the same time as the direct genetic offspring of the grandmother donor. we will be hearing more and more children suffering from identity problem. Giving birth to your own sister completely screws up the normal transition of life.
Furthermore, I feel that mother-to-daughter donation is not the only way to allow the daughter to experience motherhood. The daughter can get egg donation from people with no blood relation, this will solve the problem of identity.
Not only that, the daughter is only seven year old. By the time she reaches motherhood, technology may have been advanced enough to help her. This donation will not be necessary then.