I think it's all about passion for languages. I have bilingual children and my first was having difficulties with my native language compared to the second one. It's all individual...So the answer is
it depends
in my opinion I think there is no advantage over the children from monolingual. Children from bilingual families take 2 different languages as one. So in some sense there are still monolingual...
here is some paper:
Because a key expectation parents have is for their child to perform well in school, it is important for parents to know that bilingual children and monolingual children develop their learning abilities at different speeds. Children learning two languages learn each language more slowly than monolingual children learn their native languages. It is easy to understand why -- children have a limited amount of time with which to dedicate to listening and reading language; if a child is bilingual, he will split that time between the two languages, which slows his learning speed. This often affects the academic performance and communication skills of bilingual children, which can cause stress in the family. In a sense, the average school is set up to go at a monolingual speed, which might outpace bilingual children.
http://everydaylife.globalpost.com/child-development-bilingual-vs-monolingual-household-7371.html
Bilingual 12-year-olds perform worse at school than their monolingual peers, a researcher at Sweden's Örebro University has found.
http://www.thelocal.se/20110323/32766