How could an adult putting his saliva in direct contact with an infant’s open wounds possibly not be dangerous???
If a doctor spit on the instruments he was using to examine (not to mention inserting like shots, tongue depressors etc.)your child with would you be O.K. with that??
As far as the “we have been doing this for the past 3500 years” argument;
1.)The infant mortality rate was so high for the vast majority of those “3500 years” that we do not sit Shiva for a baby that dies within the 30 days. I wouldn’t use the fact that they did anything then as a reason to continue doing it
2.)For most of the “3500 years” the vast, vast majority of people did not believe that diseases were caused by germs. The idea that somebody’s saliva could carry an STD or disease would be impossible to their minds, so of course they had no problem with it!