When a man urinate in a toilet bowl (those type where you have a pool of water in the bowl and you can flush everything down), and it creates foams in the water as if there is soap in the water, what is the source of the foam? because the urine is rich in Sperm? or, any other reason?
Every quarter, I run a urine lab in my introductory Human biology course.
After everyone gets over feeling uncomfortable by having others see their urine, it turns out to be one of the most popular labs we do.
Interestingly, I usually get at least one female asking me the same question - quite confidentially. "Why is it that male urine seems to have more bubbles that female urine?"
My off-the-top-of-my-head response has always been in the method of collection. I suggest that males, perhaps because of greater force, or distance, are able to "blast" the sample and thus create more froth. Alogical hypothesis, I thought, but never tested.
I could not think of a very accurate way to test the hypothesis, and still maintain the high standards of our institution and still retain my job. But last week, I figured out a way.
When the student returned to the lab with their samples in hand, I asked three males and three females, if I might have a third of a test tube of their finest for a test I was going to run. They agreed, and the only identifying marks were the classic male and female symbols on the test tubes. Each test tube was covered with parafilm, and then each was shaken (not stirred) for five times (or 5 "shakes").
All three of the male samples created 2-4 cm. "heads," while all three female samples could only muster about 0.5 cm. worth of effort. After standing for 1 hour, the male samples still had about 1 cm. of foam, while the female samples were entirely bubbleless.
Obviously, the bubble factor of urine is not due to the method of collection, but shows a definite dimorphic difference. I realize that the sample size was small and the experiment lacked the proper elegance to be recorded in a journal. Still, while trying hard not to appear sexist, it does appear that males are better bubble-makers than females.