Cute Kitten: Sheldon's favourite childhood lullaby "Soft Kitty" proves you really don't even want an true kitten for this trope.- Sheldon does not, even so, take pleasure in LOLCats an electronic mail of these from Penny gave her her 1st strike. Darwinist Desire: Sheldon tries to come across which of his friends is the best genetic match for his sister, on the hope that the offspring may be a genius like him.