The Leicester couple has a daughter, Charlotte Mariethoz that has a rare blood condition called diamond blackfan anaemia and doctors say she needs a stem cell transplant from a genetic match to survive.

Her parents will now use IVF to attempt to have a “designer baby” to save her.

Tissue testing involves taking one or two cells from an embryo when it is around three days old.

If there is a match for the existing child, that embryo will be implanted in the mother’s womb so it can develop.

Once a baby is born, stem cells are removed from the umbilical cord and stored for four to six months when the transplant to the sick child can take place.

This entire proccess is called having a “saviour sibling”.