Ritchie Striker from Bridgeport makes very expressive children (and cute too!). In my experience his eyes dominate a bloodline as much as the infamous Steel lips. Here's a couple of shots from eight generations of his descendents. Other than Sherman Bagley marrying Ritchie's daughter, all of the genetics through the generations were randomly generated game sims.
Mother on the right, daughter on the left. Her eyes are Ritchie's through and through. It gives a serene quality to the expression at rest, but that disappears when the emotions start showing!
Same kid, much different expression.
Ritchie's great-granddaughter, still the same eyes. Never seen a sim able to 'well up' with emotion before, but she was a champ at it thanks to his genes.
Ritchie's grandson and great-great-great-granddaughter. Her eye shape was a bit different by that point, but they were still Ritchie large.
If the daughter is generation one, this guy is generation eight. The eyes are still large and still have that hint of droop at the corners.