Does the current NEC require each bathroom, in a residetial dwelling, have a circuit dedicated to a GFCI receptacle?

No.


If a 20A bath receptacle circuit serves ONLY receptacles in baths, oddly enough the code minimum would allow ALL receptacles in all baths to share one circuit.

If the 20A bath circuit is confined to one bath it may also serve other loads like lighting or vent fans, along with the receptacles(s).