Living on farm during pregnancy could mean less chances of asthma to the child. The baby is less likely to develop eczema and hayfever too, it seems.
A New Zealand study seems to support the conventional wisdom that a down-to-earth life could make you that much more robust.
The researchers suggest that exposure to animals and the bacteria they carry might be strengthening the foetus's immune system.
Writing in the European Respiratory Journal, they said exposure before and after birth halved the risk.
But experts warn some animals carry infections which may harm the baby.
The research, carried out at Massey University, adds to other studies which have suggested that living on a farm, with regular contact with animals, during the early years of life, could cut the risk of asthma and other allergic diseases.
But the study of more than 1,300 farmers' children goes further, suggesting that this protection could start building even before birth.
It found that the greatest apparent protection - a 50% reduction in asthma, and an even greater reduction in eczema and hay fever - was gained by children whose mothers had been exposed to farm life during pregnancy, and who currently lived on a farm.
The reasons why this might happen are unclear, although they are likely to be related to the way that the child begins to develop its immune system.
Living on a farm means frequent contact with animal bacteria, perhaps through the consumption of unpasteurised milk, or contact with the animals directly.