First, a little nitpicking: one of the parents can take at most 12 months off, so there is no "14 month contract".
Second, the whole thing can be way more complex. In Germany a mother has her job secured for the moment she announces to be pregnant to until the child is 3 years old. So one could decide that will take the Elterngeld for 12 months but actually just go back to work 18 months, and the employer has no way of stopping it.
Third and final point: NONE OF THIS MATTERS! Trying to find the "fairness" in this is nothing but some incredibly naive exercise. Like most things in life, salaries are not determined by the amount of value produced but rather by market value of labor. Risks when dealing with labor force should be already priced in.
