twinkle in one's father's eye

plural twinkles in their fathers' eyes

1. colloquialhumorousidiomaticA notional look of anticipation or hope (either for sex or a child) in one's father's eyes at or around the time of one's conception.

   “Thirty years ago you would not even have been a twinkle in your father's eye.”

   2010, Max Overton, Jim Darley, Sequestered, Sequestered Books, →ISBN

   2 more examples

   Kimberly handed him a whisky and said: "So's that, my boy. Forty-eight-year-old Glenlivet. This was a connoisseur's drop before you were a twinkle in your father's eye."

   1975, Terry Blake, The Fig Tree, Aim Publishing (1975), page 26

   'Don't you take the piss out of me, sonny. I was doing this job when you were just a drunken twinkle in your father's eye!'

   1992, Martina Cole, Dangerous Lady, Headline Publishing, published 2008, →ISBN

   Synonyms: glint in the milkman's eye, twinkle in one's daddy's eye