Newborns are not confused by 2 different languages they are taught from birth onwards. Learning 2 native languages will even help them learn new languages as they get older.
In the past, people were concerned about babies being exposed to two languages in their early childhood. Bilingualism was looked upon with suspicion and children lost the valuable opportunity to learn two or even more languages with perfection. It will never be as easy as learning a language than when you are a child which is why nowadays there are numerous books and articles written about the subject multilingualism. Kids are able to acquire up to 4 native languages without having any disadvantage over their monolingual friends.
As people are increasing traveling, doing business in other countries and defining themselves are world citizens, there are more international couples than ever before in history. Americans are dating Brazilians, Germans are dating the French and Italians are dating Norwegians. Dating across borders has almost become a fashion and it is not that uncommon anymore to meet a couple that communicates in a third language or where one spouse is obliged to learn the native language of his/her partner to faciliate the communication process.
As a natural consequence, kids are born into a cross-cultural environment where 2 languages play an important role in their everyday lives. It is hard for many parents to deal with this new phenomenon and with sceptics who still allow themselves to degrade bilingual education. There are certainly many things parents need to consider and before rushing into teaching their kids a number of languages should inform themselves about the subject.
This is a number of articles on the subject which will take your fear and scepticism and teach you how to teach your kids more than one native language.