String Like Thread In Human Feces. Very Thing Like Floss. I Don't Think It's Worm From My Research On The Net So Far. Any Other Thoughts?

From the description in your question, it sounds like that your daughter is almost definitely suffering from thread worms. You say that she is not experiencing itching but she still may have thread worms because they do not necessarily cause itching in every case.

Threadworms are small, thin and white with a thread-like appearance that infect the human gut. They are most common amongst children but can affect all ages. They live in human intestines for around 5 to 6 weeks and then they die but before this, the females will have laid their eggs around the anus.

The main symptom of threadworms is the child complaining about itching around their bottom, which they then scratch and cause their bottom to feel very sore. There are a couple of things you can do yourself as a parent to check if your son or daughter as threadworms before you take them to a Doctor.

If you suspect that they may have threadworms then you can check by looking at your child's bottom. If they are reluctant you can always try and check when they are asleep with a torch. Part the buttocks and take a look at the anus. If they have threadworms then you may be able to see a couple. Don't be alarmed! Just take your child to the Doctors as soon as you can. The Doctor may also ask you to do a 'sticky-tape' test which is then sent off to a laboratory to confirm if your child has threadworms.

Treatment for threadworms is given in the form of a medicine to kill any threadworms in the system and any eggs before they hatch. If one person in the house has threadworms then it is likely that everyone else in the house will too even if they do not show any symptoms. So if one person has it then everyone will have to get treatment.

For more information on threadworms, symptoms to look out for, how they spread and how they are treated, visit this website: www.patient.co.uk/health/Threadworms.htm

Did anyone ever figure out what this was? This has been going on with me for quite a few years off and on now, getting slightly more noticeable around my period time. I have been to different doctors and they have never heard of it before.

You can but treatment for threadworms from a pharmacy to treat at home you would need to treat the whole family though

I reckon this string-like non-moving white coloured material is just a string of protein. Nothing to worry about.
But I wonder what makes our intestine to produce that and why.

They thought my son had this, turns out it wasn't thread worms, though we were all treated for it.  We still have no clue but now he is having sulfur smelling gas and a fever, no diarrhea so they are still lost.  He is a cancer patient so this may not be helpful.

The white thread like strings can be intestinal parasites most probably the thread worms. These worms cause itch but not necessarily. Another reason can be irritable bowl syndrome. Visit to a doctor for stool test and appropriate treatment. For more details visit Thread worms.