Hi Doug,
I'm not impugning the behavior of the pet rat! I have no doubt it's a friendly clean fellow. Just that I think close contact to humans is a bad idea because of unknowns. Rat's have their own ecosystem of bacteria and viruses. some are obvious, others are latent. We know very little about the risks to be able to quantitate them, except in bad social situations.
I'm just thinking as a microbiologist and physician that we do not need to get the ecosystems fused! The rat does not come with any health certificate, or does it? I've never thought about that. Maybe there are such pets screened for pathogens? However, there are only limits to what one can test for. Most folk won't ever get an illness they notice. However, one might get an infection which has long term delayed consequences. I cannot say.
I for one wouldn't want to expose growing children so intimately to rodents. I just think of HIV crossed from monkeys to man and flu from fowl to man, so I'd avoid such risks, low as they are.
However, I'm over fussy! I have no doubt it's a lot of fun. Still near the face, seems a bit far. At least, hand wash afterwards! Excuse my fussing! That's just my nature concerning pets. Some folk have their pooch lick them in the mouth, go figure. To me it's not even fair to the dog!
Asher