If there was an embryo with the TC gene, then the clinic would automatically destroy it, refusing to put any back that carried it.
"But we knew there was no guarantee how bad the TC would be, if the baby would have it at all.
"It could have been as minor as a slight hearing problem, to being born with no face whatsoever. It was 50/50."
Vicky was sterilised after her three previous children and was not allowed IVF on the NHS because she was already a mum of three.
Simon's mum paid for the £6,000 treatment privately and the couple, from Wymondham, Norfolk, are paying her back in monthly installments.
The procedure at Bourn Hall Clinic, Cambridge was successful – but a 16-week scan showed that Alice had inherited her father's genes.
Simon said he still has to deal with strangers pointing and laughing at him and once on holiday a crowd even gathered to take pictures of him.