should GIRLS be CIRCUMCISED too?

It's mostly to ensure they won't get raped. Simply because there is no hole to leave sperm cells in if you catch my drift. I oppose to these practices.

As for circumcising boys is okay if it is for health reasons, not for religious stuff, same goes for girls, but I don't see a reason why this would be beneficial for health...

I heard this kind of report when i was in university.
Some countries have this kind of practice for religious belief and culture. It is called "clitoridectomy", where some of the private parts of a woman will be cut or stitched. The outer labia of a woman is cut because it is regarded as dirty and looks disgusting. With the stitching, it is one way to ensure the woman's virginity for her future husband before getting married.
I think this is a cruel practice to control women in some countries where women have lower social status and freedom than men.
There was also a research that this kind of practice poses a danger to the woman's health.

Your question asks, should GIRLS be CIRCUMCISED too?

Well, I dont believe girls should be circumcised at all, and I dont believe that boys should be either, UNLESS THERE IS A MEDICAL NEED.

It is something that I consider totally barbaric.

Here a link that explains what is done: http://en.wikipedia.org/wiki/File:FGC_Types.jpg