The claim: Allergy problems run in families.
The facts: It is well known that traits like hair and eye colour, height and even certain aspects of personality can be inherited. What about allergies?
The environment may get most of the blame but scientists have found that allergies like asthma and hay fever have a powerful genetic component.
Once study of 344 families, for example, found that when neither parent had a history of asthma, only 6 percent of children went on to develop it.
However, in families where one parent had the condition, 20 percent of children had the diagnosis; in families where both parents had it, 60 percent of children had it too.
More compelling evidence comes from dozens of studies on twins. Generally, when one identical twin suffers from hay fever, asthma or eczema, the other twin has it in 50 to 80 percent of the cases. In fraternal twins, the percentage drops to about 25 to 40 percent.
The bottom Line: Environment and genetics both contribute to allergies, but studies suggest that genes play a critical role.
- The New York Times