Fortunately i don't have one of my own to add...well not yet. This is what happened to my sister. She and her boyfriend had a strong feeling they were pregnant. They were quite young and completely naive when it came to pregnancy and were terrified to tell anybody else about it so they thought they'd find out for sure by doing a HPT - before they shared their secret. So my sister sends her boyfriend out to buy a HPT from Coles. He returns saying he got the 'bulk pack' so they could be 100% sure "it has five in it" - he says. My sister looks at the box he bought and sees that he hasn't bought a HPT but infact a OPK. They eventually discovered they were preg - but at least they had a funny story to tell at the same time!!!!!!