Now any child she had would effectively be her own genetic half brother or half sister but her partner's child, which seems to me needlessly complicated. There are other, simpler, options:
1) Live a full and happy life as a useful member of society without having children.
2) Adopt one or more of the millions of unwanted children around the world.
3) Have a baby using donor eggs from a donor of her own generation, who could even be a friend or relative.
But also Flavie already has medical problems - Turner's syndrome causes impaired growth, learning difficulties and early menopause - is it really fair to encourage her to try for an IVF baby, subjecting herself to intrusive medical proceedures over months and years with absolutely no guarantee of success? Her mum insists "I do not want to oblige her to use the eggs; I want to give her the option.", I can't believe from the child's point of view it will really feel like that.