 The study will measure the effect of the antigen exposure on the presence and time to presentation of: 1 early clinical markers for asthma development frequent wheezing, wheezing without colds, rhinitis, and atopic dermatitis; 2 early immunologic markers for asthma development eosinophilia, immunoglobulin E; and 3 development of a T-helper phenotype Th-1 vs Th-2. Investigators will characterize the Th phenotype by measuring the whole blood lymphocyte response to stimulants, focusing on Th1 IFN-gamma, interleukin IL-12 and Th2 cytokines IL-10, IL-4, IL-13, as well as real-time reverse transcriptase polymerase chain reaction RT-PCR with PCR amplification TaqMan to quantify RNA transcripts. Clinical and immunologic markers will be measured up to 3 years of age. 