NEW YORK (CBS NEWS) -- Positive pregnancy tests can be found for sale all over the Internet, CBS New York reports.
And people are snapping them up - with less-than-ethical motivations, according to CBS New York's Alice Gainer.
One mother from Dallas did not want her identity revealed, but she does want people to buy her positive pregnancy tests. She talked about one woman who took her up on the offer.
"She wanted to trick him into thinking she was pregnant, so he would drop everything so I gave her two tests," the woman said.
Buying and selling others' pregnancy tests is the latest trend on the Internet. Those involved in the trade said the buyer's motive is often to trap a man - and that is not all.
"Ninety-five percent of the girls just want to lie to get a man," the seller said.
And the sellers know that.
One Craigslist ad posted last year by a central New Jersey woman read: "I am pregnant and will sell you a positive pregnancy test. These will be taken right before you're ready to pick them up. Wanna get your boyfriend to finally pop the question? Play a trick on mom, dad or one of your friends? I really don't care what you use it for."
Another ad from Buffalo promised no judgment at all. It read in part: "Ever since I became pregnant, I have been asked numerous times for a positive test, so I decided to start charging for it! I will test the same day you want to pick it up! I don't care what you use it for, not my business!"
"You can tell the girls who are up to no good," the seller said.
Ethics and morality aside, relationship expert Dr. Jane Greer said having to use a phony test to get your partner to commit is clearly a bad sign for the future.
"If you're buying one of these, it really is a statement that you're not on solid ground with the person you are in a relationship," Greer said.
The Dallas pregnancy test seller said there are other motivations for buying the tests besides snaring a partner.
"One girl said she just wanted to play a trick on her mom," she said.
And still others may have more sinister plans. Authorities warned people to be careful how they use the purchased positive tests.
"For example, if a married man is having an affair and he tried to break it off with the girl, and she became upset and decided to present this fake pregnancy test and demand money, otherwise she would tell the spouse, that would be a level of blackmail," Overland Park, Kansas, police Officer Gary Mason told CBS affiliate KCTV-TV, Kansas City.
Whatever the reason for buying it, many said they find the idea inconceivable.
"That's playing with people's emotions," one man said. "You don't mess with stuff like that."
"I wouldn't want to be on the receiving side of that," another said.
"It's just like any other con - cons are no good," a woman said.
But mothers-to-be who sell the tests for as much as $30 each said it is just the latest commodity online.
"It's a neat, marketable skill - it's kind of unique. You're only going do it so many times in your life," the Dallas woman said.
Some expectant mothers are going so far as to sell their urine online, as well.