Freckles form as a result of sun exposure. UV light triggers melanocytes in the skin to produce melanin in response to UV damage as a protective measure. For people who form freckles it is because the melanocytes in certain areas produce significantly more melanin than the surrounding melanocytes, causing an uneven distribution. Redheads have the MC1R gene which dramatically increases the likely hood of overactive melanocytes. The MC1R gene loads the gun while UV exposure pulls the trigger for freckle formation. A baby who has never been exposed to the sun does not have any freckles as a result. Because the sun in Northern Europe is not nearly as strong as it is elsewhere, there isn’t much of an evolutionary pressure for melanin to be evenly deposited to form a strong protective layer.