I have a concrete slab and was wondering if I can glue down engineered hardwood in a full bath?

While it is not the greatest idea to install wood in a full bath due to the excessive moisture it is certainly possible. If you must and only if you must be sure to leave adequate expansion space. Furthermore if a shower or tub is used often be prepared to counter the moisture as best you can. If the tub or shower is rarely used then the better chance you have at a floor that doesn't buckle. Also plan on separating the bathroom from other rooms with a t molding or turned board just in case.

Hope this helps

Just imagine one time with excited kids in the tub is all it takes to ruin wood in a full bath.
unless your right there with them.