A group of 2N boys and 2N girls is randomly divided into two equal groups. What is the probability that each group has the same number of boys and

A group of 2N boys and 2N girls is randomly divided into two equal groups. What is the probability that each group has the same number of boys and girls? 

I have no clue how to even begin solving this. The "N" part of the question confuses me a little bit. Would it be possible to get a solution with steps and explanations?