I've used this product before and had very clear negatives, so I know that it can give a correct negative reading. Last month, my husband and I found out that we're infertile, and we may not be able to have a child on our own. Imagine my surprise, then, when this month I got not one, but two, faintly positive pregnancy tests! Imagine my even greater surprise, then, when my temperature dropped and AF showed up on the very day I had my second positive. I am beyond heartbroken and very upset for the false hope I was given.