I just happened to have the Today show on late one day, not paying attention, until it finally registered what they were talking about. The parents were discussing the little girl's disease, neurofibromatosis. It is a common disease, 1 in 3000 children, that it seems nearly no one has heard about. It has severity from so mild a person doesn't know they have it (and are a carrier) to severe. They said the first sign was the presence of brownish "birthmarks" by the age of 2 called "cafe au laits." That up to 3 was normal, more than 3 they needed to keep an eye on, and more than 5 were a nearly positive indication that the child had the disease. The show had been discussing how the little girl's marks looked like ladybug spots. I still wasn't paying much attention. Then they said that they could be pretty much any size or shape.
My mother and I just happened to have been discussing one of my 2yo childcare kids' large jagged-edged birthmarks and how he had gotten more over the last year, so it was fresh in my mind. I ran over to him and pulled the top of his diaper down. The 3 "birthmarks" on his tummy, now had two additional showing up below them, and another one was on his knee. He had 6 cafe au lait marks. His parents got on it immediately and have a referral from an optomologist, since the disease causes nodes to form on the eyes around 3, and a dermatologist to set base lines. They are also thinking about genetic testing, but aren't sure of the need, since he shows the signs and there is no cure or preventative measures to take.
If your child, or one that you know, has brownish birthmarks, you may want to check out the internet information on this disease and discuss the possibility with your pediatrician. It is also important to have a child,s eyes checked at 3, as this will also show progression if the disease is there.