Recently, here in New York, there has been a great deal of discussion about circumcision. Specifically, the need to regulate and/or ban metzitzah b'peh.
For the uninitiated, metzitzh b'peh is a procedure that dates at least as far back as the Gemara. After the infant is cut, the mohel uses his mouth to stop the bleeding and draw out any stray blood. Yeah. Ick. Gross-out factors aside, there are those who would argue that a bris performed without metztzah b'peh is invalid. And the Board of Health is concerned about this little procedure because infants have been coming down with herpes--which the Board has linked to metztzah b'peh. Of course, those on the side of metztzah b'peh argue that the chances of catching herpes from a mohel are impossible or at least very small.
Pardon me while I get all post-modern, but I don't think so. OK, in the Gemara nothing was understood about germ theory. Nowadays, we stop the bleeding with sterile sutures, not saliva.
Consider, if you will, the penis.
The human penis is rich with blood vessels. Blood flow is what causes the physical effects of arousal, colloquially known as an erection, woody, or hard-on. And these blood vessels, like all others, flow to and from the heart. Should anything get into those blood vessels, they have a one-way ticket to a mean infection.
Now consider the germ.
Herpes simplex is caused by a virus. Viruses, unlike bacteria, are not true cells. They are simply bundles of DNA. Scientists are not even sure how to classify them. And they cannot be destroyed by antibiotics. Herpes simplex is a particularly vicious little bug that has, at this time, no known cure. Now, in an adult, it manifests itself as sores on either the mouth or genitals. In the mouth, these are commonly known as cold sores. However, to an 8-day-old infant whose idea of immunity is whatever got handed down in Mommy's colostrum (and G-d help the bottle-fed, who don't get all their mother's antibodies), herpes simplex can cause brain damage and death.
So now you have a mohel placing his saliva (which is filled with bacteria anyway, even without the herpes virus) on an open wound, on an organ filled with blood vessels, on a fragile newborn. Do you want to take the Vegas odds that everything will be fine?