I don't know what it is about twins, but I've been intrigued by them my whole life.
Aside from these adorable bunnies, the first real twins I encountered in my life were also the very first African-Americans I encountered: Michael and Michelle. I had great fun playing with them at my grandmother's church, and they were pretty amused at my delight at their skin color, hair texture, and twin-ness. It was several years before I met more twins: two identical sets, both in the same dance company!
From there it kept going: from my obsession with Sweet Valley High books, to my various science reports on twins raised apart (I can't even imagine!) Of course I double- and triple-checked with my parents to make sure I wasn't really a twin.
When I was pregnant, I was honestly disappointed both times that I wasn't carrying twins. (My friends with twins just roll their eyes at me for my naivete.)
Given how active I was as a toddler, I can assure you that my parents were pleased I was a singleton!