Hi, i am 37 male with with no problems of health, but just started to note dark fluffy fiber like substane( small amount once in a week).I have also noted similar fiber like substance in semen also..i am just woundering is it coming from urinary bladder or kidneys ?other any other reason my weight is the same,but at times i feel like my stomach bloated. when i met my doctor the last time he said the urine dip test and regular kindey,liver functions are all fine..still has the same issue ongoing..Please let me know ur opinion