No, because the point is that "most readers" are male. The advertisement should be unisex. If a woman picks up that journal - whether just looking for want ads

No, because the point is that "most readers" are male. The advertisement should be unisex. If a woman picks up that journal - whether just looking for want ads or because they are legitimately interested in the topic - they should be considered with complete equity to any male candidate. The point isn't where you advertise, it's if you target. You can target by geography. You can target by education. You can't target by sex.