The Twins in Rune Factory 2: One Birthday Gift or Two?

I was surprised when more than one player asked whether one Birthday Gift should be given to BOTH Twins or whether each should have her own gift. MARMALADE is their special Birthday Gift item and their birthday occurs on 29 Autumn. I had suspected that one Gift would suffice as their heart levels increase together, and they even share the same Mock Wedding Event with your character. I recently tested the result of giving each a gift on her Birthday, however, to make certain. Here is the little 'Event'.