For most little kids, their birthday is the happiest most important day of the year; one that they look forward to pretty much all year; as soon as one birthday is done, the next one is being looked forward to!
So how is this very special day to be handled when it comes to a situation of shared parenting?
In general of course, the child would spend the birthday with the parent with whom primary custody rests, and if the birthday falls on a visitation day, then it can be spent with the other parent. This is of course in theory, whereas in fact there could be several problems.
It at all possible, both parents can remain present to help a child celebrate the birthday; this would be the civilized thing to do, and the child would be the happier for it.
However sometimes this is either practically or emotionally impossible. When this is the case, one could celebrate two birthdays for the child, one with either parent so long and there is no attempt made to outdo one or the other.
A special time to celebrate a special day for a child could be doubly special for him or her.