Argh, it's a crime this article isn't free, but it's worth reading
Lack believes that a child becomes tolerant to a variety of food proteins through exposure in the first six months of life. Lack’s research has gradually gained influence with leading allergists, including Hugh Sampson. Sampson believes that some eighty per cent of infants who are allergic to eggs or milk will outgrow the allergy by their teen-age years, and that preventing them from being fed products with these foods may prolong the time that takes. In January, 2008, the American Academy of Pediatrics released a clinical report by Mount Sinai’s Dr. Sicherer and other researchers that overturned the expert advice of the past decade. Gideon Lack is disturbed by what families now face. “Basically, we are all in limbo,” he said. “Even the experts are not certain what to advise.”advise.” http://www.newyorker.com/reporting/2011/02/07/110207fa_fact_groopman