We definitely don’t want children to get sunburned, we also don’t really like them to get suntanned much. That’s true, in general, for skin and dermatology in children. This is the general advice that we give to all our patients.
As for the role of sunlight in CMN, nobody has done a study as to whether UV light and your exposure to sunshine makes a difference to your chance of getting CMN. CMN develops in the brain first, it’s not something that is affected by UV light.
It is possible that the amount of sunlight you are exposed to as a child might make a difference to your chance of getting Melanoma as an adult, and that is just the same for all of us.
Sun exposure in childhood is important for your chance of getting Melanoma later in life, so in general we would like to avoid that if possible- to avoid sunburns and suntan where you can.