In defense of cats and dogs, even the ones that cause allergic reactions, it looks like they may offer more than love and affection (as if that was not enough) to their owners.

"Jane Heyworth at the University of Western Australia in Crawley, and colleagues found that incidences of gastroenteritis – commonly called stomach flu – were significantly lower in young children living in homes with pets, than those living without."

Cats and dogs protect kids from stomach bugs – NewScientist.com