Matt Ridley is the author of provocative books on evolution, genetics and society. His books have sold over a million copies, been translated into thirty languages, and have won several awards.

My latest Mind and Matter column in the Wall Street Journal:

One of the delights of science is its capacity for showing us that the world is not as it seems. A good example is the startling statistic that there are at least 10 times as many bacterial cells (belonging to up to 1,000 species) in your gut as there are human cells in your entire body: that "you" are actually an entire microbial zoo as well as a person. You are 90% microbes by cell count, though not by volume-a handy reminder of just how small bacteria are.

This fact also provides a glimpse of the symbiotic nature of our relationship with these bugs. A recent study by Howard Ochman at Yale University and colleagues found that each of five great apes has a distinct set of microbes in its gut, wherever it lives. So chimpanzees can be distinguished from human beings by their gut bacteria, which have been co-evolving with their hosts for millions of years.

My latest Mind and Matter column for the Wall Street Journal:

These days the heritability of intelligence is not in doubt: Bright adults are more likely to have bright kids. The debate was not always this calm. In the 1970s, suggesting that IQ could be inherited at all was a heresy in academia, punishable by the equivalent of burning at the stake.

More than any other evidence, it was the study of twins that brought about this change. "Born Together-Reared Apart," a new book by Nancy L. Segal about the Minnesota study of Twins Reared Apart (Mistra), narrates the history of the shift. In 1979, Thomas Bouchard of the University of Minnesota came across a newspaper report about a set of Ohio twins, separated at birth, who had been reunited and proved to possess uncannily similar habits. Dr. Bouchard began to collect case histories of twins raised apart and to invite them to Minneapolis for study.

My latest Mind and Matter column for the Wall Street Journal:

Part of the preamble to Agenda 21, the action plan that came out of the Rio Earth Summit of 1992, reads: "We are confronted with a perpetuation of disparities between and within nations, a worsening of poverty, hunger, ill health and illiteracy, and the continuing deterioration of the ecosystems on which we depend for our well-being."

Update: a couple of small corrections inserted in square brackets below. Thanks to Stephen Coles of UCLA.

My latest Mind and Matter column in the Wall Street Journal