Child: cord blood —heparin green top (cell pellets and supernatant), red top (serum), EDTA purple top (plasma, WBC-DNA); age 3 (early childhood) - EDTA purple top (plasma, WBC-DNA), heparin green top (plasma, RBC); age 3 (early childhood) Immune Substudy - EDTA purple top, heparin green top (room temp - stimulation supernatants, plasma), and heparin green top (cold - RBC, plasma); age 7 (mid childhood) - EDTA purple top (plasma, RBC, WBC-DNA), heparin green top (plasma, RBC), grey top (plasma), urine, hair; early teen - EDTA purple top (plasma, RBC, WBC-DNA), heparin green top (plasma, RBC), 2 ml grey top (plasma), urine, hair