51�Թ�

This is one of the facts that played into the complicated decision Lucy and Ollie made to opt for pre-implantation genetic testing, a special type of IVF where embryos are created outside of the body and screened for the genetic condition.

Lucy and her husband Ollie married at Kew Gardens two years ago and are now ready to start a family - but there are complications to consider.

Her health journey has involved swimming, lifting weights and many runs with Ollie tethered to her as her sighted guide.

Meanwhile Lucy will inject herself with trigger shots to stimulate the follicles within her ovaries to increase the number of eggs produced which will be retrieved, and then made into embryos with Ollie's sperm.

Those embryos will be "shuffled about" so Lucy and Ollie don't know which will be selected in terms of gender or other genetic qualities, and implanted into Lucy, who will carry the baby to term.