Wood sprites
(Book)

"Even though they attend a school of gifted students in New York City, child geniuses Louise Mayer and her twin sister Jillian have always felt alone in the world, isolated by their brilliance. Shortly before their ninth birthday, they make an amazing discovery. They're not alone. Their real mother was astronaut Esme Shenske and their father was the famous inventor, Leonardo Dufae. They have an older sister, Alexander, living on the planet of Elfhome, and four siblings still in cryogenic storage at the fertility center. There's only one problem: the frozen embryos are scheduled to be destroyed within six months. The race is on to save their baby brother and sisters. As a war breaks out on Elfhome and riots start in New York City, the twins use science and magic to plow over everything standing in their way. But when they come face to face with an ancient evil force, they're soon in over their heads in danger.--