In a growing number of American homes, the family dog is more than an affectionate companion.

For children with severe allergies, some of those dogs are literal life-savers.

Medical service dogs trained to sniff out peanut products, tree nuts and other allergens are becoming more common, especially as the number of young children with food allergies is on the rise.

But some owners say they're having mixed success convincing schools, businesses and operators of other public venues that the dogs must be accepted as service animals, just as dogs whose owners' disabilities are more apparent.

The Americans With Disabilities Act specifically includes them, but many state laws haven't been updated to add that language.

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