
For decades, twin sisters Caitlin and Grace Leggett, from Cardiff, believed they were fraternal. It took a harrowing leukaemia diagnosis for Caitlin at the age of 23 to uncover the astonishing truth: they are, in fact, identical.
The 23-year-olds had always assumed they were dizygotic twins, formed from two distinct eggs fertilised by separate sperm. Growing up, their bond was exceptionally close, sharing a multitude of hobbies, including years of competitive athletics. Their academic paths also intertwined, both attending the University of Bristol – Caitlin studying Psychology and Grace Neuroscience, the latter coincidentally going on to complete a Master’s in stem cells and regeneration. They even shared a student house, remaining the best of friends.