Hi Been There,
I don't think drug testing companies check for gender, they usually check for the "standard 5" set by the Govt: Cannabinoids (marijuana, hash), Cocaine (cocaine, crack), Amphetamines (amphetamines, methamphetamines, speed), Opiates (heroin, opium, codeine, morphine) and Phencyclidine (PCP).
How do you plan to do this? Are you going to pee in a plastic bag and tape it to his leg, then hook up a tube to it and tape it to his penis? It may be more involved than you think. Whatever method you choose, you might end up with a leaky container of warm urine and a smelly mess that is hard to explain/ ignore.
Did your buddy know about this test 3 months ago? You can always "prepare" by not using for a few months. Even die-hard pot heads <cough, cough> have done this. It's quite a lot of pressure to put on a friend, asking her for clean piss and possibly jeopardizing her job.
I don't like drug testing either, or the drug laws of this country. It's nice of you to want to help your friend, but don't screw yourself in the process. -suz
Also, FYI: If you use a product to "clean out" your system of drug traces, and the test picks up the adulterants in the urine sample, that sample will be considered positive for drugs.
Alcohol may be legal, but it is a drug, and some companies do test for it (e.g. Airlines, military).