Hello Dr Bob,

Thanks to your last reply.

That's my second time I sent this question.

I've re-done a thorough research about the anatomy of male genitalia. In short, it turns out that information out there is inconsistent. In Wikipedia, two separate entries of `Foreskin' and `Mucous membrane' yield contradictory results: the former says `the glans penis (head of the penis) and glans clitoridis and the inside of the prepuce (foreskin) and clitoral hood are not mucous membranes', while the latter says that `the inner foreskin is a mucous membrane like the inside of the eyelid or the mouth. ' By the way, according to `glans penis' of wikipedia, `The epithelium of the glans penis is mucocutaneous tissue.'

By the way I found out that the foreskin is composed of Langerhans cells which are identified as receptor of HIV virus (this information comes from OU Handbook of GUM and HIV medicine).

I have discussed these issues with a psychiatrist (the reason being that I feel I'm extremely worried over the whole HIV/STD thingy) who warned me that I shouldn't be doing penis-to-penis side-along rubbing and penis docking any more because `it's rubbing of mucosal tissues. HIV/STD virus is bound to pass between. Why would you take such risks?'

In your last reply (http://www.thebody.com/Forums/AIDS/SafeSex/Archive/TransmissionSexual/Q194250.html), you said that the transmission risk of dick-docking is essentially nonexistent and *implied* that penis-to-penis side-along rubbing does not pose any transmission risk because the only mucous membrane of the whole dick (including shaft, foreskin, glans penis) is the lining of the urethra from the pee-hole up to the bladder. But I didn't mention that I'm uncircumcised. There's plenty of inner foreskin whose very nature is highly suspicious of mucous membrane and which is full of Langerhans cells.

So my questions are: (1) could you please reiterate your opinion on the transmission risk of dick-docking and penis-to-penis side-along rubbing, citing the reason behind?? What if one of us shot the load? Would the load shoot right at the urethra during docking??? (2) should we put on a condom while we do dick-docking and penis-to-penis side-along rubbing? (3) should I do a circumcision, as some studies from Kenya(!) suggest it reduces the risk of transmission of HIV and other STDs? Do you believe it?? (4) why are Langerhans cells cited as susceptible to HIV infection? What role does it play ?? (5) why is the term `mucous membrane' so important in HIV infection? What is it anyway?? Would HIV or other STDs get across the membrane and infect others??

As bothersome as I am, I sincerely do hope that you wouldn't find my queries offensive or devious in any way. Debate leads to better understanding. In order for me to have some sort of peace, could you painstakingly answer my questions??

I promise I will donate USD150 to your charity fund.

Yours Nate.

Hello Nate,

1. My opinion regarding HIV transmission/acquisition related to frottage (penis-to-penis rubbing, "dick-docking") remains unchanged. It is not considered to be a risk. Could you shoot a load and hit the urethra? Yes, it's theoretically possible, although not very likely, that the spunk would actually come into significant contact with the urethra's mucous membrane.

2. If that would make you feel safer and less anxious, sure. Personally, I don't feel it's necessary.

3. The studies do indicate that male circumcision decreases the risk for acquiring HIV. However, if you follow safer sexual techniques, I don't feel it's necessary.

4. Langerhan's cells (dendritic cells) play an important role in the initiation of HIV infection by virtue of the ability of HIV to bind to specific cell surface receptors of these cells. This allows efficient presentation of HIV to CD4 cells that then become infected. The foreskin contains Langerhan's cells.

5. A mucous membrane is a thin layer (membrane) that lines all internal body passages that communicate directly with air outside the body, such as the respiratory and alimentary tracts, and which has specialized cells or glands that secrete mucous. HIV can permeate mucous membranes, but it cannot permeate intact skin. The foreskin is not a mucous membrane. However, it is a specialized type of skin and HIV can be taken up by the Langerhan's (dendritic) cells located within the foreskin.

I certainly don't find your queries either "offensive or devious." It can be somewhat confusing to try to explain complex details of anatomy or the function of specialized cells in a forum such as this forum. So the anatomy lesson is over for today.

Thank you for your generous tax-deductible donation to the Robert James Frascino AIDS Foundation (www.concertedeffort.org). It's warmly appreciated.

Dr. Bob