There have been several reports recently of tests being touted online so women can use them to con men.
Some women use them to force a marriage proposal from their lovers, while others use them to extort money from men they've slept with.
In the latest case, a businesswoman posted a photo of herself on Facebook clutching three pregnancy tests - all clearly showing the two pink lines needed for a test to be 'positive'.
She captioned it: "Once again... selling pregnancy positive tests for $50 each. Need money for my kids."
The unnamed woman added: "Make that man yours... forever!"
Facebook was quick to take down the posting, Closer reports, but the pregnant mum was unrepentant.
She wrote: "I don't know why my last post was deleted. This page says no rules."
Incredibly, the woman's actions appear to be far from rare.
Earlier this year, a pregnant woman offered her positive test for $20, adding: "I don't care what you need them for."
But who would buy them? According to a report in The Guardian, women snap them up so they can trick their partners into proposing to them.
But even more sinister, others use them to blackmail men they've slept with.
A woman in Dallas forked out for a positive pregnancy test to seek revenge on her cheating lover.
She said: "He texted and said he isn't sure who he wants to be with and I think I handled it well for what a cheating, lying dog he is. I would like the last laugh out of this. I will give some girl $40."
Sellers on eBay market positive pregnancy tests - 'fake and real' - as 'pranks'.
The products, which sell for £4.99, show two lines or a plus sign indicating a positive result.
One listing reads: "Have fun pranking friends and family with this positive test :)"
One mum told Parentdish: "These kits are so offensive. Perhaps somebody would find them funny, but I'd be devastated if someone played a trick on me with something like this."
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