19National legislation which does not take into account, for the calculation of the amount of parental benefit, periods of employment completed under the Joint Sickness Insurance Scheme of the European Communities is likely to dissuade citizens of a Member State from working within an institution of the European Union situated in another Member State since, by accepting employment with such an institution, they lose the right to benefit under the national sickness insurance scheme from family benefits to which they would have been entitled had they not accepted that employment (see to that effect, My, paragraph 47).