the hypothetical has a possibility of happening that a dude has a chick give him urine so he can hide it and use it for his UA. They could find out that she's pregnant when she didn't kow it herself.
Pure ancient wives tale that goes back to the birth of workplace drug testing. It was often recited by goofy-looking antidrug "speakers" in an effort to discourage cheating the drug tests. I find it hilarious that theres many of the unwashed who still fall for this piece of propagandical BS.

The thing is drug testing devices have no ability to determine pregnancy. They only determine the presence of drugs. The lab would have to use a testing device designed specifically to determine pregnancy. Pregnancy tests are totally outside the scope of drug testing, so therefore, labs operating in the US are prohibited by law to perform pregnancy tests on a urine sample collected for a drug test. Pregnancy tests can only be performed under a detailed written authorization by the donor.

And why all the discussion about the best way to cheat a drug test. Read Passing Drug Tests by Kenn A Biscranium and find out how to rapidly and healthfully detox for any random UA.
Why spend money on a book on passing drug tests when all of the information is found online for free?

The time spent on hawking books could be better utilized on researching how drug tests work and how testing devices work. This information can be found online by making some good use of your favorite search engine (its your freind).

And its all free :thumbsup: