User blog comment:Vulture345/The "Lincoln is Adopted" Debate/@comment-27264989-20170408205728/@comment-24001488-20170409214805

Lucy dyes her hair, and Lincoln's hair is from his grandfather. As for why Lucy is pale, it could simply be she doesn't like the sun or she could have a medical condition. Also, people don't have to look alike to be related...

http://nypost.com/2015/03/02/meet-the-bi-racial-twins-no-one-believes-are-sisters/