Siamese kittens are born white because of the heat inside the mother's uterus before birth. This heat keeps the kittens' hair from darkening on the points. Though rare, cats can contract canine heartworms. People who are allergic to cats are actually allergic to cat saliva or to cat dander. If the resident cat is bathed regularly the allergic people tolerate it better.
Studies now show that the allergen in cats is related to their scent glands.
Cats have scent glands on their faces and at the base of their tails. Entire male cats generate the most scent. If this secretion from the scent glands is the allergen, allergic people should tolerate spayed female cats the best. Cats do not think that they are little people. They think that we are big cats.