Have you heard of zoonotic diseases? These are diseases that animals can spread to humans... even seemingly healthy animals. I used to work with veterinarians and most of them will advice against sharing your bed with a pet. Even the CDC is against this practice.
Please take the time to check these sites:
http://www.aolnews.com/2011/01/20/letting-sleeping-dogs-lie-in-your-bed-can-kill-you/
http://www.nbcnews.com/id/41235440/ns/health-pet_health/t/out-sack-cat-sleeping-pets-carries-disease-risk/
http://www.vetinfo.com/dogs-sleep-human-bed.html
I'm thinking that we're more likely to die in a car accident yet that doesn't stop us from driving. My daughter has been a vet tech for about 8 years. I'd have her ask the vet about this but we already know that he sleeps with his 4 dogs.
I've been sleeping with either a cat or dog for over 50 years. I think I'm probably immune by now but will take my chances.