Michael Mosley tells the story of our middle weeks in the womb - when we become an individual. At 8 weeks we all appear to be the same, but in the next stage of our development an incredible series of transformations takes place that makes each of us unique. Our instantly recognisable faces finish forming, we become left or right handed and our skin takes on its colour. Inside, we are developing our own bespoke immune system and as our brains are being organised, our personalities start to form. It's even believed that our feelings about sex and gender may be established long before we are born. Told through a series of surprising, moving and inspirational human stories, the show discovers that the path to becoming ourselves is mind-bogglingly complex - that there are an infinite number of possibilities that makes each of us unique.