Re:My twelve year old
My name is Hank, I started laser treatment when I was five years old. I am now 22. I think the doctor you saw might not have known what he or she was talking about. I strongly suggest finding a doctor that knows what they are doing. If you go to the left of this page, under resources click on find a physician and then find go to your state or one close to you and have your daughter checked out. She might be more comfortable with a female doctor.
The only reason I could think why the doctor said that is because around your daughters age puberty sets in.
After puberty when I stoped growing so did my birthmarks.
I hope this all helped and email me back if you have any other questions.