Can sunlight bring out birthmarks in toddlers? When my daughter and I came back from the pool, I noticed a small light brown circle on her arm. I thought it was a stain of some kind at first, but it's definetly a birth mark.

I would just keep an eye on it, If it concerns you call her doctor. It could be a freckle or a new mole, kids have them pop up all the time very quickly my daughter did. Just make sure it doesn't change or grow or get darker over time.

Is it the size of a freckle or mole or bigger? I have 5 kids and two of them were not born with visible birthmarks but as they got older they became noticable. They are light brown, flush with the skin and a light tan color. I was very surprised because I had never noticed them before it was as if they just appeared. I would have the dr look to be sure but that's what it sounds like to me. I don't think the sun would do anything it might just happen to be the time you noticed it.