Those who favor representative studies claim that one should not generalize a study to a population whose characteristics differ from those of the study population

Those who favor representative studies claim that one should not generalize a study to a population whose characteristics differ from those of the study population. A study of smoking and lung cancer in men would tell nothing about the relation between smoking and lung cancer in women. Give the counterarguments. (Hint: if the study were conducted in London, would the results apply to those who lived in Paris?)