Most manufacturers will state that only IP65/67 equipment be installed to a bathroom environment. Most ceiling lights on a bathroom are usually outside of the zones and from that respect no special conditions apply however the regs state that items must be suitable for environment and conditions so you should take into account water vapour/steam, potential for water being splashed etc, provided the circuit supplying the bathroom is RCD, & other factors have been considered I can't see a problem, but we as electrician's can only advise you accordingly, you the customer can decide what you require within reason.