Randi Zuckerberg, Facebook CEO Mark’s sister and owner of her own digital company, is raising a tech-savvy kid. While she says she tries to balance how much time her 2-year-old son, Asher Tworetzky, has in front of the screen, he’s already a natural. “I try to really limit,” she told us last week. “I want him to get outside and play like a normal kid, but at the same time I see 2-year-olds who are really comfortable . . . I don’t want him to be behind his peers who are having all this exposure to tech — so it’s always a bit of a balancing act.” Zuckerberg says her son can open and play on an iPad, and he likes Peekaboo Barn and anything that involves trains.