Case C-149/10: Judgment of the Court (First Chamber) of 16 September 2010 (reference for a preliminary ruling from the Diikitiko Efetio Thessalonikis — Greece) — Zoi Chatzi v Ipourgos Ikonomikon (Social policy — Directive 96/34/EC — Framework agreement on parental leave — Interpretation of clause 2.1 of the framework agreement — Person granted the right to parental leave — Parental leave in the event of the birth of twins — Meaning of ‘birth’ — Taking account of the number of children born — Principle of equal treatment)