"barring a biological reason for the FP" I think that's an unwarranted assumption. Sure, another source of false positives is contamination or user error even

"barring a biological reason for the FP" I think that's an unwarranted assumption. Sure, another source of false positives is contamination or user error even, but other than that most FP are indeed due to a (usually unknown) biological reason. I'm reminded of a friend that was just positive she was not pregnant. She tested herself three times with three different pee stick brands. She was wrong. They all use the same chemistry, and for some reason something in her body interferes with those tests.