BOSTON -- Child psychologists and environmental activists are concerned about the increased marketing of makeup to children as young as 3 years old.

With colorful, youthful packaging bearing names like "bubble yum," and Disney star "Hannah Montana," the products appeal to young girls.

"It makes me feel like a teenager," one girl told Boston television station WCVB.

The Environmental Working Group recently tested 20 teenage girls from across the country for a buildup of chemicals that are found in many cosmetics. The group discovered that the blood and urine from the girls studied tested positive for the presence of an average of 16 toxins. However, the study couldn't prove that the girls contracted the toxins from the makeup alone.

The toxins present in the girls studied can be dangerous. Some of the chemicals found have been linked to cancer, and some have been known to alter hormones.

"That's really a great concern because during the teen years that's when bodies are maturing," said Cindy Luppi of the group Clean Water Action, in Boston.

Luppi specifically said the brain and reproductive systems of young girls develop during their teen years.

Local psychologist Sharon Maxwell has other concerns about girls getting hooked on makeup and beauty products.

"Think about the kind of daughter you want to end up having," Maxwell said. "Do you want the sexiest girl in high school? Or do you want the most well-rounded, balanced girl we hope understands her sexuality in the context of all the other aspects of her life?"

Maxwell said it's fine for a child to play with makeup occasionally, but she added, "It's quite another thing to make yourself up and go out there acting like a grownup with makeup on. That’s not play. That's the real world, you know?"