Babies who eat fish between the age of six and 12 months have more protection from wheezing and breathlessness than those who don't.
However, the window for action is only those six months as the benefits of giving your youngster fish before or after that age is negligible.
The results, based on more than 7,000 children in the Netherlands, support one theory that early exposure to certain fatty acids in fish protects against the development of asthma.
Expert Jessica Kiefte-de Jong, of the Erasmus Medical Center in Rotterdam, wrote in the journal Pediatrics: "Introduction of fish between six and 12 months - but not fish consumption afterward - is associated with a lower prevalence of wheezing.
"A window of exposure between the age of six and 12 months might exist in which fish might be associated with a reduced risk of asthma."
Between 40 per cent and 45 per cent of parents of children who did not eat fish until after their first birthdays said their children wheezed, compared to 30 percent of children who first ate fish when they were between six and 12 months old.
That works out to about a 36 percent decreased risk of wheezing for the children who first had fish between the ages of six months and one year.
Concern over seafood allergies prompts some parents and doctors to delay introducing fish into babies' diets, but this research turns that fear on its head.
When did you start feeding your children fish?
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