This journal continues to be fascinated by the hygiene hypothesis—that is, that insufficient exposure to infection in early childhood might predispose towards later asthma and atopy. Two related papers from the ALSPAC study group in Bristol, UK explore this further. The first details hygiene practices for a large number of UK babies and produces the counter-intuitive result that mothers of lower socio-educational status keep their babies cleaner. One reason might be their greater use of chemical household products. The companion paper looks at associations between hygiene at 15 months and atopy by 3.5 years. The results support the hypothesis so it might well be that too sterile an environment is harmful. Recalling his own parental practices, the editor now understands a little better why his offspring did not inherit his asthma.

See pages 26 and 30