STILL waiting (impatiently) for my cup. However, I've been researching, and I found the video that was posted a short while ago (on cups causeing Endometriosis). As a result of a combination of curiosity, procrastination from actual work, and a genuine interest, I've done some research. I'm compiling what info I can find from both sides. To be honest though, there seems to only be one person on the "cups cause it" side and many on the "don't be ridiculous" side.
I'm going to post it into my blog, so check that out if you like. It's kinda still a draft, so any furthur info would be appreciated, and please excuse the current editing state. I'm searching for more sources on the "cups cause endo" side but honestly, all I've found so far is people quoting that one guy, or affiliated with him.