From Mr Robert Schroeder.
Sir, Lawrence Dritsas (Letters, November 23) is correct to say that, as humans mature, the gene that produces lactase shuts down because the body has presumably been weaned from mother’s milk, expecting never to consume it again. What is unique about human behaviour is that, once we reach adulthood, we voluntarily consume milk that comes from a different species.
Robert Schroeder, Ewing, NJ, US
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