Rome, May 1—(AP)— Premier Mussolini, in the hope of increasing the number of Italian offspring, has caused the lowering of the legal marriage ages from 18 to 16 for the husband and from 15 to 14 for the wife. It is explained that the govern mental measure will have a certain sociological value as well, inasmuch as it will afford a means of com batting the practices of common law marriage or “free union” which is particularly prevalent in industrial centers