It is a very modern dilemma. Should you hand your child a smartphone, or keep them away from the devices as long as possible? As a parent, you'd be forgiven for thinking of a smartphone as a sort of Pandora's box with the ability to unleash all the world's evils on your child's wholesome life. The bewildering array of headlines relating to the possible impact of children's phone and social media use are enough to make anyone want to opt out. Apparently, even celebrities are not immune to this modern parenting problem: Madonna has said that she regretted giving her...