The man behind the Tumblr photo blog Reasons My Son Is Crying is accepting photographic contributions from parents worldwide in attempt to explore the "universal culture of toddler" - and the best ones will be entered into a contest to win a camera.

Greg Pembroke, from Rochester, New York, began taking mid-tantrum photos of his infant sons Charlie, 22 months, and William, three-and-a-half, and captioning the images with the (mostly unreasonable) reasons for the boys' tears.

For more information on the contest go here.