In contrast to reports that Willow Palin recently had a pregnancy scare, the 16-year-old sister of single mom Bristol tells In Touch that she isn’t having sex. “I’ve learned from her choices. I learned to not have sex,” Willow explains, referring to her older sibling, who gave birth to son Tripp at just 18. “Sex is bad. The only efficient way of birth control is not to have sex.” Though Willow clearly adores her nearly 2-year-old nephew, she says she's hardly ready for motherhood herself. “I don’t want a baby this young!” she insists. A protective Bristol backs her little sister up, adding to In Touch, "Willow is not pregnant!"