Lex's mother was raped by Others, so the story goes. She gave birth to Lex as a result, and took her hatred out on the girl.
"...Rune strode to Lex with her hand out before she realized the girl couldn’t see her. Slightly uncomfortable, she put her hand down. “I’m glad you’re feeling better, Lexi.”
Lex didn’t smile. She turned her face toward Rune. “Thank you.”
Rune gestured at the two chairs positioned in front of her desk. “Ellis can grab another chair if you’d all like to sit down.”
Before Rune could back away, Lex shot her hand out and wrapped her fingers around Rune’s wrist.
Carefully, she slid her fingers down until she was holding Rune’s hand, her expression solemn.
Just the tiniest bit, her body began to vibrate.
“Lex,” Levi said. “Maybe--”
“Quiet,” she said."