system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Melanin and aging

Mostly in India and near neighboring countries, kids are born with lighter tone or colour and with aging they turn dark or brown and become more closer to their parents skin tone. What changes in the body causes this to happen? Normal parent talk is this happens because teens run around in the hot sun, i suspect that's not the full story.
gpt
Certain genes that control melanin production are not activated until the babies grow older or during puberty.

You will see this with people with lighter hair or eye colors as these children may be born with blond hair that darkens with age or with blue eyes that eventually changes to a darker color. The same would happen with someone with someone born with a lighter color skin which gets darker with age.