I'm still struggling to understand the development of the child's immune system. A few months ago Dr. Zimmer and I exchanged some discussion of "when the child's immune system becomes mature" -- I cited some studies suggesting 6 years of age (for some factors). Now today I read in the following in TIME Magazine, in a story about babies born with HIV virus who later show no traces of the virus in their system (not just antibodies, but actual virus was detected when they were young): "A newborn's immune system isn't fully functional until around 18 months...." Now, I would love to be able to cite this to doctors who claim that immunities in breast milk are insignificant after "X" amount of time (usually well under one year). Anyone know where this 18 month figure might come from, or what portions of the immune system they might be referring to? ---------------------------------------------------------------------------- ------- Katherine A. Dettwyler, Ph.D. email: [log in to unmask] Anthropology Department phone: (409) 845-5256 Texas A&M University fax: (409) 845-4070 College Station, TX 77843-4352