CHICAGO - The number of kids with food allergies is mysteriously soaring - peanuts allergies alone have doubled in recent years - but scientists do not agree on the cause. | Neglect puts children with food allergies at risk | 'Gluten free' may not be

One theory is simply more awareness. Parents today may be quicker to seek a medical diagnosis for their children's illness than in the past.

Another explanation is the "hygiene hypothesis," which argues that some children's environments have become too sterile. With fewer germs to fend off, a child's immune system overreacts to common food proteins.

Other theories abound. Kids eat more pre-packaged foods and a wider variety of dishes containing potential allergens. Or an increase in births by Caesarean section has robbed babies of the protective power of microbes present in the mother's vagina. But few studies confirm such speculation.

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