At this day of age, I would think twice about skipping grades for more than a year.

For course materials, you can always find enough books, online classes and problem sets and community to interact with. So there is no problem if your child wants to advance his or her learning in any subjects.

So I would ask myself -- what does my child get out of skipping? Nearly every time I thought about it, the final answer was "shortened childhood and joining the workforce early".