Possible Clues:

• May-December marriage issue
• Space in a relationship
• Dad's flipped about scrambled egg -- a difference between him and mum?
• Possible source of a romantic power imbalance
• Such as divides old man and young woman, endlessly arising
• Just one year, for Venus and Serena Williams
• May-December romance feature
• Romantic obstacle
• Sibling statistic
• Impediment to romance, perhaps